Category: Genetics

How genes and environment affect children

Memory cards

OK, I have to fess up. I am moving house this week and have nothing prepared. So here is an essay I wrote a while back to explain my work in gene-environment interaction. I know, it sounds scary, but its really simple and I’m sure that this “story” will help you understand.


I’m here at Mr. Almighty’s Cloud Street Headquarters to interview him on his plans for a family friendly casino.


Mr. Almighty, it’s great to meet you! Tell me the concept for your casino.”


Mr. Almighty: It’s ingenious really. My casino actively encourages participation of whole families. Although single people are encouraged to come, it’s in the hope that when they have children, they can continue to come here as a family and I’ll have a continued source of customers!


Very clever. What sort of gambling facilities will you have? Slot machines, roulette, ‘Blackjack’?”


Mr. Almighty: Ah, well! I’m a ‘Blackjack’ man myself, but my enthusiasm spreads to all card games and so I’ve dedicated my casino to cards. We’ll have ‘Poker’, ‘Snap’, ‘Bridge’, ‘Old Maid’, ‘Rummy’, as well as ‘Blackjack’ off course. In fact, you name a card game and we’ll certainly be playing it. I’ve divided the venue into sections so that a different card game will be played in each, so called ‘gaming environment’.


A very catchy name.”


Mr. Almighty: Yes. I think our advertising boys did a good job on that one.


What’s so special about a casino dedicated to card games for families?”


Mr. Almighty: Hah! Well, unlike other casinos, there’s a twist. My casino will be exclusive: ‘Members Only’ I mean…


There’s nothing new about that!”


Mr. Almighty: Wait, I haven’t finished. On joining, I deal all members 14 playing cards. They must play with the same 14 cards that they were dealt on joining for the duration of their membership. The only exception will be for members’ children. We anticipate there’ll be several billions as the casino expands, so I’d be here all day dealing out cards to kids if there was no exception made! So, I’ve devised a simpler plan for them. They will be blindfolded and asked to randomly pick their cards from the hands of their parents: half from their mother, and half from their father. From then on, the same rules apply: “You play with the cards you’re dealt”! That’s the slogan our advertising department is adopting for our poster campaign!


But there’s a terrible flaw in your plan! What if I joined and received a terrible hand? I’d have to play with that for the duration of my membership and keep losing! I might as well give up!”


Mr. Almighty: No, no – that needn’t happen. You, like so many others, see things at face value and don’t see the complexities in the matter. Whether you win or lose depends not only on your cards but a whole host of factors. For starters: how well you play the game. Parenting is potentially important for this, at least in the beginning. Even if a child has a great hand, if his parents haven’t taught him the rules of the game, he’s pretty sure to lose.


Yes, I suppose so.”


Mr. Almighty: Later on, he might have more chance to play with friends or have tuition from teachers and be able to learn skills for card playing from them.


So, his chances of success and failure might be influenced by his peer group and school environment?”


Mr. Almighty: Indeed.


But, once you’ve learnt the rules of the game, your potential winnings are still dictated by the cards you’re dealt. You’d be stuffed if you had no ‘Aces’ or ‘Picture cards’.”


Mr Almighty: Not so! That’s the beauty of my casino. There are many chances to win. As I’ve said, we play all the card games in the world here, not just one! The ‘Aces’ and ‘Picture cards’ might serve you well in a game of ‘Bridge’, where high scoring cards are valued, but in ‘Old Maid’ where they are penalized, they will cause you nothing but grief! And in ‘Snap’, well, a ‘two’ is as good as any ‘Ace’ so long as you find a pair.


O.K. So how well you do depends on the interaction between your cards and your ‘gaming environment’. A hand full of ‘Aces’ in a ‘Bridge’ game spells success, but the same ‘Aces’ when playing ‘Old Maid’ spell disaster. So the handicap I predicted isn’t necessarily so, and it’s a matter of finding the optimal combination of game played and cards possessed.”


Mr. Almighty: Exactly!


Even so, how well you do in the long run is still dependent on your cards isn’t it?”


Mr. Almighty: In some respects. I can’t say that your cards will not ultimately limit your potential but there are still further factors that could influence prospects.


Besides your cards, acquired knowledge of the game and the game being played, I can’t think of any thing else that would influence progress.”


Mr. Almighty: I see you’re not a regular card player! Otherwise you would know that there is a lot more to card playing, not least the abilities of your opponents, or ‘gaming society’ as our advertising boys like to call them.


O.k. I suppose if I were playing with novices, I’d certainly have a better chance of winning.”


Mr. Almighty: Now you’re catching on! As you can see, there are lots of ways you can still win with a deficient hand of cards. You choose a game you’ve been taught to play well, a ‘gaming environment’ where your cards are valued and where your fellow card players are suited to allow you to thrive.


So, I could look at my hand and in effect change my prospects by selecting a ‘gaming environment’ dependent on my cards.”


Mr. Almighty: Yes, indeed there’s likely to be a great deal of correlation between your cards and your selected environment. But it’s not always easy to tell from the outset which is the best ‘environment’ for your hand. I’m not going to label the environments ‘Professional Poker Player’s table – avoid unless you have a Royal Flush’ or ‘Beginner’s Bridge – you’ll win big here even if you have no Picture Cards’. What usually happens is that there is a fair amount of trial and error before some satisfactory environment is found.


But clever manipulation of the ‘gaming environment’ can make good from a poor hand.”


Mr. Almighty: Indeed. And these are just factors I’ve thought of so far. I’m sure if more research was done in this area, more significant environmental and social factors will be found to allow players who receive a poor hand to win.


“That’s amazing! But tell me, how can this venture possibly make money? You’ve said players with terrible cards can still succeed by choosing the correct ‘gaming environment’. If players got wise they’d keep winning and you’d go bankrupt!”


Mr. Almighty: Well, I have a few tricks up my sleeve. I didn’t wish to impose this restriction, but the reality is that to stay economically viable as a business, I must. I have had to impose a cost attached to changing ‘gaming environments’. You will have to start playing in the same ‘environment’ as your parents. Otherwise, I’d be bankrupt by the babysitting fees alone! If you want to change environments, you or your family will have to pay a fee, and it’s not cheap. It’s sad but true, some poor buggers get stuck in an environment totally at odds with their cards and they just carry on losing.


Let me get this straight. If my parents play ‘Poker’, then I have to start off playing ‘Poker’ even if my hand is better suited to ‘Snap’. In order to play ‘Snap’ and make it big, I need financial backing?”


Mr. Almighty: Yes. That’s the gist of it. I have to make money somehow! If only the government would give us casino proprietors more money, I’d love to let my members play in their optimal ‘gaming environments’ and watch them flourish. Unfortunately, I can’t afford to do that.


Isn’t there another way? What if between my parents they have the cards to give me a ‘Royal Flush’ which would make me almost guaranteed to win at ‘Poker’. Couldn’t they pay a fee to engineer it so that they select which cards I inherit, rather than my picking them randomly? Or, could I modify my hand and change certain cards for ones that might suit my circumstances better?”


Mr. Almighty: That certainly would allow you to win. It’s a contentious issue though! Some would even call it cheating! But I can see where you’re coming from. If I was constantly playing to lose with no prospect of winning, and with the knowledge that my children would inherit a poor hand and little financial resource to change their lot, I’d quite wish to be able to do the same thing too. I often see players with no ‘pairs’ or ‘Picture cards’ continuously losing their savings at the ‘Poker’ table and I think, what if I could give him a pair of ‘Aces’ or two. Unfortunately, if I sanctioned card changes, all my members would be queuing up to change their cards and I would have no peace! As it turns out, there are many intelligent members who’ve devised ways of ‘card modification’. But there’s no point changing your cards willy nilly. The trick is to research your ‘gaming environment’ and ‘society’ and strategically find the correct card to change. By changing specific cards, some have been able to turn the tides of their fortune. Sometimes, it can rejuvenate whole families who’d lost hope, not to mention the benefits to their future generations. Other times it’s used for the wrong purposes, and I totally disagree with it, but am powerless to stop it. It’s really up to members to decide how much ‘card modification’ they can tolerate. There’s a committee that monitors it. I try to keep out of it, though they often try and bring me in to their debates!


But it could ultimately affect your business. If all this ‘modification’ was allowed to go on, everyone would have ‘Aces’ and ‘Royal Flushes’ in their hand and you’d go bankrupt!”


Mr. Almighty: Not necessarily. The members can modify cards behind my back all they like, but they need ultimately to bear in mind that if everyone had ‘Aces’ and ‘Royal Flushes’, the whole ‘gaming society’ would change. There’d be no members with losing hands and you’d have to be an even better card player to succeed. There will always be winners and losers just the same. In any case, don’t you know the first thing about casinos? The house always wins. I have one last trick up my sleeve and that is, I have the right to close down any ‘gaming environment’ I choose, at any time.


How would that insure your success?”


Mr. Almighty: Well, if all my members were gaining ‘Aces’ and ‘Royal Flushes’ to win at ‘Poker’, then they would be taking a large gamble. I could close down all my ‘Poker’ tables and turn them into ‘Old Maid’ gaming environments at my whim. That way, I could turn all the winners into losers and losers into winners whenever I choose!


“Caution and the importance of environment is the order of the day then?”


Mr. Almighty: Indeed.


It certainly sounds like a fascinating venture! One thing I wondered though, your advertising guys seem to have coined great names like ‘gaming environments’ and ‘gaming societies’, but couldn’t they think of a more catchy name for the cards?”


Mr Almighty: Yes, they’re working on that, so far, they’ve only come up with ‘genes’.


‘Genes’. That might just take off! Tell me, what are you going to call your new casino?”


Mr. God Almighty: Well, actually, the prototype has already been running successfully for several millennia, and I think I’ll launch the real thing with the same name as it’s a good a name as any. I call it ‘LIFE’.


Why there is no autism epidemic


Strictly speaking, the term “epidemic” should be reserved for infectious diseases. I realise that the term has now bled into everyday language to mean a large rise in prevalence rates for anything (e.g. obesity epidemic), but the original clinical definition was to describe the spread of infectious diseases (e.g. ebola epidemic). I’m a clinical terminology pedant; I lose sleep over people that call a “fascination” an “obsession”, so you can imagine my loathing of the headlines of “autism epidemic” to describe the increased numbers of people being given a diagnosis of autism. The reported autism prevalence rates have increased from around 1/100 to 1/68 (that’s about one child in every 2 state school classrooms). However, even if the lay terminology is accepted, the rise in numbers of people diagnosed with autism has more to do with changing diagnostic classifications and awareness than an environmental hazard that shock-headlines would like us to anticipate. There are many press and internet articles that discuss this, but I didn’t feel that they fully explored the territory, so here is a researcher and clinician’s view of the reasons for increased rates of autism.

Why do boundaries in classification change?

Autism is primarily a genetic disorder and the genetic basis of autism is pretty much undisputed now. Although environmental hazards may play a role, these are generally on the basis of a pre-existing genetic vulnerability. There are several known genetic disorders already identified that highly predispose to autism (e.g. Fragile X, tuberous sclerosis, neurofibromatosis), but these disorders account for only a small proportion of the total incidence of autism. The bulk of people with autism have what is called “idiopathic autism” the genes for which have yet to be identified (although several genes are suspected and are undergoing rigorous going over by scientists, none have been conclusively proved).

The identification of genes for autism is a tricky problem, as it is not a single gene that is wonky in autism. If it were, then it would have been identified long ago, like other single gene defects (cystic fibrosis, tuberous sclerosis) and we would be able to test for it readily with a genetic test. It is likely that there are multiple genes, say 6 (this is an educated guess), that are all required in order to generate the disorder. These genes are common, and both you and I are probably carrying several of these genes right now and have already handed them over to our children. Like in the National Lottery though, it is quite common for individuals to have a few of the numbers that come up, but it is much rarer to have all 6 numbers together. In the case of autism, only the people with all 6 genes get autism. Also like in the National Lottery where 5 numbers will get a small pay-out, people with 5 genes may get a watered down version of autism.

Scientists have been using all the tricks available to them to try and elucidate the precise gene combination. A few years ago, the computer capability to do Genome Wide Association Studies (GWAS) (where you sequence the entire genome of subjects with autism and the entire genome of subjects without autism, bung the lot in a very big computer and get it to output the combinations of genes that are common to people with autism but not present in the people without) was supposed to lead to a major breakthrough in autism research. It didn’t. The reason being that as all scientists know; if you put sh*t data in, you get sh*t data out. The conclusion amongst researchers was this: the people that we are defining as “autistic” and “not autistic” are wrong. If there are non-autistic people in the “autistic” group; or more likely, autistic people in the “not autistic group”, this will mess up the results.

How are we currently diagnosing autism and is it correct?

The current classification manuals for diagnosing autism (and other mental health problems) are the DSM (used in the USA) and ICD (used in Europe) manuals. My husband has a similar book for “diagnosing” if a mushroom that he finds on the heath is poisonous or not. There is no blood test or scan, only the basic science of observation and interrogation. You might, (and some do) dispute the validity of such classification manuals, but it has thus far served my husband, who has a penchant for putting foraged fungi into his mouth, well (i.e. he has correctly been able to avoid the death cap by consulting his book). A hundred or so years ago, manuals like these were used to diagnose everything from brain tumour to Down’s syndrome (doctors of old diagnosed brain tumours from symptom check-lists including things such as headaches and vision problems, and having round faces and “Mongolian eyes” suggested Down’s syndrome). By fine tuning the classification and studying the people identified, it has become possible to find causes and cures. If classification had not initially taken place, cures would not have been found. This is where we are currently at with autism, fine-tuning the classifications based on new research findings, the precursor to elucidating cause and generating treatments and cures.

The by-product of fine-tuning the classification manuals is a change in disorder prevalence rates. Old classification manuals stated that all children with autism had a learning difficulty, this was found not to be true and newer classifications reflect this. Older classifications state that autism is largely a disorder that only affects boys; newer classifications describe what symptoms may look like in girls. In previous classification manuals, it was stated that if a child had ADHD, they could not have autism, this is now known not to be the case and indeed 30%-50% or so of children with autism have ADHD. New classifications allow this diagnosis to be made. Thus, over the years, with increased research pointing to a wider distribution of the core symptoms of what “we” scientists and clinicians see as autism, and with each revision of the classification manuals, the description of “an autistic child/ person” has changed vastly. An intelligent, inattentive girl with core features of autism, diagnosed with autism today would not have received a diagnosis even 50 years ago, and I am pretty sure that our current classification will not be the last revision.

Some might call this changing boundary of diagnosis pharma and clinical collusion to “medicalise natural variation”; but as I mentioned previously, I prefer to see it as a scientific journey we are halfway/ dare-I-even-believe three quarters of the way through, towards an understanding of aetiology and generation of treatment and cure. Who knows, when aetiology is found, the boundaries may yet shrink back.

The conclusion to the journey may not be far off. Whilst geneticists are relying on better patient classifications to do genetic studies on, neurophysicists are relying on better patient classifications to do neuroimaging and functional neuroimaging studies on. We are already almost at the stage where a computer can accurately predict if a person has autism or not based on their brain scan (Ecker 2010). It may be within my life-time (my grandpa lived to 104 years so I have an optimistic life-expectancy) that the diagnostic classification manuals can be ditched for a brain scan or set of genetic tests; just as has already happened in the case of brain tumour or Down’s syndrome.

Improving awareness

Raising awareness of health conditions is a great thing. Many people have benefitted from the increased awareness of autism over the last 10 – 20 years. Autism is a condition that babies are born with and that they will grow and live with life-long. There is no current treatment for the core symptoms, let alone a cure, but the correct support for the child, family and school, can have a significant impact on outcomes. Improving awareness encourages people to come forward for assessment and diagnosis and access support; improving awareness leads to requests for more and better services; improving awareness leads to higher profile and political will to spend on autism; improving awareness leads to better acceptance and understanding of people with autism. I can say nothing but good things about raising the profile and awareness of autism. In 1988 when Rainman was first released, I had never heard of autism. I think if a film about autism was released now, the majority of people would have heard of the condition. Without a doubt, the number of families seeking autism assessments for their children has increased, and this can only mean increases in diagnostic rates.

An epiphenomenon to improving awareness that has also contributed to increased prevalence rates is due to what can be discretely called “diagnostic inflation”; or what can be better understood as “overdiagnosis” or “misdiagnosis”. It is an unpopular but real notion. It is one thing to “raise awareness” of autism, but it is another to educate about autism. I think if I surveyed a group of 100 parents, they would all have heard of autism but I think that only a handful of the 100 parents surveyed would be able to give a passable definition of the core symptoms of autism.

Why stop at parents? Teachers, GPs, paediatricians, child psychologists and child psychiatrists, especially those that trained ten or twenty years ago when autism was relatively unknown and unsexy may not be up-to-date on autism and certainly many fewer will have completed and maintained specialist training on autism diagnosis. Couple this with the improved awareness from parents of the diagnosis and the political will to allow access to substantial resources (welfare and educational) only for a diagnosis of autism and you have a system that will favour increased diagnosis.

I think that now that the job on awareness has been done, we need to work harder on the education front.

Has there been any real increase in autism at all?

This was the topic of discussion at the last Royal College of Psychiatry conference I went to. The consensus was that there was, but that this real increase was much less dramatic than the increase accounted for by classification changes and increased awareness. Many studies have focused on insults in pregnancy and environmental toxins. The research on these has yielded minor or inconsistent results, certainly nothing that alone would account for the real rise seen. The only factor that was given significant credibility was that of the increased age of the mother AND FATHER of autistic children.

Whilst awareness of the effects of maternal age on children’s outcome has been well-publicised (increased risk of Down’s syndrome as one well-known example), the risks of older dads has been less so. Yet, paternal age has long been established as a risk factor for schizophrenia (Malaspina 2001), and there is now emerging evidence for association of paternal as well as maternal age with autism (Reichenberg 2006; Durkin 2008; Sandin 2012).

It is ironic that many people sought to blame a vaccine for increasing levels of autism, in some instances sparking fears of a real epidemic (of measles), when in fact, like so many other health problems, the cause may prove to be within our own life-styles.


Ecker C, Marquand A, Mourão-Miranda J, Johnston P, Daly EM, Brammer MJ, Maltezos S, Murphy CM, Robertson D, Williams SC, Murphy DG. (2010 ) Describing the brain in autism in five dimensions–magnetic resonance imaging-assisted diagnosis of autism spectrum disorder using a multiparameter classification approach. Journal of Neuroscience. 11;30(32):10612-23.

Malaspina D, Harlap S, Fennig S, Heiman D, Nahon D, Feldman D, Susser ES. (2001) Advancing paternal age and the risk of schizophrenia. Archives of General Psychiatry, 58(4):361-7.

Reichenberg A, Gross R, Weiser M, Bresnahan M, Silverman J, Harlap S, Rabinowitz J, Shulman C, Malaspina D, Lubin G, Knobler HY, Davidson M, Susser E. (2006) Advancing paternal age and autism. Archives of General Psychiatry. 63(9):1026-32.

Sandin S, Hultman CM, Kolevzon A, Gross R, MacCabe JH, Reichenberg A. (2012) Advancing maternal age is associated with increasing risk for autism: a review and meta-analysis. Journal of the American Academy of Child and Adolescent Psychiatry. 51(5):477-486.

Durkin MS, Maenner MJ, Newschaffer CJ, Lee LC, Cunniff CM, Daniels JL, Kirby RS, Leavitt L, Miller L, Zahorodny W, Schieve LA. (2008) Advanced parental age and the risk of autism spectrum disorder. American Journal of Epidemiology. 168(11):1268-76.

How anxiety in pregnancy can lead to anxious children

Fire engine

This is the last of the How to improve your child’s success before they are even born series. See Part 1, Part 2 and Part 3. OK, its pretty heavy going on the science, but if you really want to understand anxiety then its worth a read.

Most people are aware that stress and anxiety are not good for pregnant mothers. Even in 400 B.C., Hippocrates espoused the influence of emotions on pregnancy outcomes, leading to a plethora of literary dramas old and new where stress has caused the leading lady to miscarry or go into premature labour. More recently though, following Barker’s theories of foetal adaptation to the mother’s womb environment (see my post How to improve your child’s success before they are even born: Part 3), scientists have found that a mother’s anxiety in pregnancy can influence psychological and behavioural outcomes of her developing foetus over and above those caused by premature delivery.  There is now a well-established literature base linking mother’s anxiety in pregnancy to several psychological and psychiatric outcomes in children, including: anxiety, attention deficit hyperactivity disorder (ADHD), cognitive problems, changes in temperament, aggression, conduct problems and even schizophrenia (Beydoun & Saftlas, 2008; Talge et al. 2007; Van den Bergh et al., 2005).


Animals stressed in pregnancy give birth to anxious baby animals

The first evidence for this came from animal studies. Researchers found that rats and monkeys exposed to stress in pregnancy produced offspring that had long-term difficulties with attention, motor behaviour, aggression, memory and showed “hyper-vigilant behaviour” (Van den Bergh et al., 2005). Hyper-vigilant behaviour in animals is a proxy for human anxiety. It incorporates being alert to potential threat with corresponding changes in body systems to prepare to respond to threat. Think about how you would have felt travelling to work on the underground the day after the 7/7 London bombings of 2005, and this is probably a good picture of human “hyper-vigilant” state. Darting eyes on the look-out for suspicious bags with no owner, or people with over-sized back packs, slight tension in muscles, slightly increased heart rate and breathing rate, a little bit more perspiration than usual and if someone were to pop a balloon behind you, you’d probably have been ready to run. Hyper-vigilance is a good thing if you are in a stressful situation. It has served me well on many a walk home from the night-bus stop. If you are continually hyper-vigilant or hyper-vigilant in non-threatening situations like social situations or on aeroplanes; it can be very problematic and is called “anxiety”.

In animals it is easy to experiment and find out what is happening, you can wire animals up to measure muscle tension, heart rates and perspiration fairly unobtrusively. Even better, you can take blood samples and measure the levels of “stress hormone” cortisol. By doing these experiments, scientists have been studying the various effects of maternal stress on animal offspring and among several suspected effects, they have found pretty conclusively that in animals stress in pregnancy causes changes in the development of the foetal stress regulation system, the Hypothalamic-Pituitary-Axis (HPA) re-setting it to be on heightened alert.


How does the body deal with stress? What goes wrong to cause anxiety? – an analogy

What is the HPA-axis? The HPA axis is a collection of parts of the body that communicate by hormones to regulate certain bodily responses, including the stress response. In its function to regulate stress-response, it works pretty much like the emergency fire service. When you see a fire, you pick up the phone and dial 999. This puts you through to a national call centre, where you are asked which emergency service you would like. Once they realise that it is the fire service you need, they contact the regional fire control centre which contacts your local fire brigade which sends out an engine to where you are. The firemen hopefully put out the fire and call back the fire brigade centre to report that the job is done, which then feeds this information back regionally so that the case can be closed. Alternatively, if the fire has gotten out of hand, they can report regionally or nationally depending on the extent of the fire to request more engines to help.

The hypothalamus (a region in the brain) is the national call centre. When the eyes see threat, they alert the hypothalamus. This lets the brain’s pituitary gland, (regional fire control centre) know that there is a threat and a stress response is required. The pituitary communicates with the kidneys (local fire brigade), which then provides the stress response: the steroid hormone cortisol (fire engine). The fire engine goes out to sort the problem. Cortisol does this by going to the heart and making it pump harder, it goes to the lungs and makes it breathe quicker, it goes to the sweat glands and makes them produce sweat, it goes to the muscles and makes them tense and ready for action. All so that you can either fight or flee the threat.

If a city undergoes a heat wave and there is an increased propensity to fires starting and burning out of control. The fire service would probably request more resources on standby and be on heightened alert to send out more engines. More engines than needed might be sent out to small fires to ensure that they did not catch and turn into large fires. This is precautionary and helpful in the short term, but is an over-reaction if continued long term, beyond the time of realistic threat. The same thing happens to our body’s emergency response system. If there is a history of heightened stress, the body responds by increasing the base level of cortisol in the blood stream and increasing the amount of cortisol released in response to stress. This is not a problem if there is continued threat, but if the situation calms down and the body does not down regulate its stress-response system, the result is persistent anxiety.

In animals at least, it has been shown that the animals themselves do not need to have been exposed to stress for their bodies to be placed on heightened alert, they merely have to be exposed to their mother’s heightened alert system in the womb. Thus in animal experiments, giving pregnant mothers injections of cortisol equivalent substances can cause their children to have higher base levels of cortisol and heightened cortisol response when they are born and with continued effect into adult life (Van den Bergh et al., 2005). These animals went on to display a range of long-term behavioural and cognitive impairments. This can be thought of as part of Barker’s hypothesized foetal programming whereby the foetus exposed to high levels of maternal stress hormone predicts a hostile environment and prepares itself by adapting its HPA-axis to best cope with impending fight for survival. Where the resulting environment is actually not that stressful; the HPA-axis is now not working properly and leads to a range of problems.


Who cares about animals? What about humans?

Stressing humans to study anxiety is rather unethical. Shockingly, it used to be allowed and “Little Albert” is a classic case in psychology literature. Little Albert was a 9 month old boy who was not afraid of rats and was given a rat to play with. A dastardly psychologist John B. Watson wanted to see if it was possible to cause a phobia of rats. Every time little Albert touched the rat, a man stood behind him and banged a piece of metal with a hammer making a loud noise scaring little Albert. Needless to say, after a while of this, Albert became afraid of rats and stopped going near them, proving it is possible to induce a phobia[1]. No wonder experimental psychology has a bad name!

These days, we are thankfully not allowed to do such things, but it does mean that extrapolating work from animal studies into humans is harder. We have to rely on stress that occurs naturally in the lives of pregnant women rather than purposefully causing stress in order to study its effects on offspring. Natural and man-made disasters have been used to study the effects of anxiety in pregnancy.

Studies of children who were in the womb of mothers affected by 9/11 showed that these children were born with lower birth weights even though they were born at term, compared to children conceived following 9/11 (Berkowitz et al., 2003). Infants whose mothers were pregnant during the 1998 Canadian ice storm that led to electricity and water shortages for up to 5 weeks scored lower on mental development indices and tests of language development compared to other children, even after taking into account birth complications, birth weight, prematurity and post-natal depression (La Plante et al., 2004).

It is not just extreme stress such as a national disaster that can cause effects. Studies have also used questionnaires asking pregnant mothers about their levels of stress at varying times in their pregnancy and then studied their children at varying ages from newborn to adolescence. In general the link between maternal stress and impaired offspring outcome is borne out, sometimes even with a direct dose-response effect[2] (Beydoun & Saftlas, 2008; Talge et al. 2007; Van den Bergh et al., 2005). Results from different studies vary as each study is different in terms of the stress they are measuring (some studies ask for work stress, bereavement, marital stress, criticism from partners, or just how anxious you feel), the time in pregnancy the stress occurs (studies vary in studying stress in the first, second or third trimester), and the outcome and age of children they are studying (some studies look at language and development in the first year, others look at ADHD symptoms in childhood and yet others look for anxiety and conduct problems in adolescence). Despite this, the majority consensus of all the studies is that there is a significant negative effect of maternal pre-natal anxiety which can have lasting effect. In this way, it is not just your DNA that is biologically influencing your child’s outcome, but environment, via biological mechanisms.This is epigenetics, the new buzz in child psychiatry research.


Interesting finer details

The theory regarding differences in timing effects is that this relates to timing of brain development. Throughout pregnancy the developing foetal brain goes from a neural tube to a baby’s brain which is a complicated journey. Different parts of the brain are forming throughout the 40 weeks, and the effects of insult to the brain at a particular period in pregnancy will depend on the part of the brain that is forming at that time. So for instance, a brain insult (such as anxiety) occurring at the time that the language centres in the brain are forming may lead to language deficits down the line.  It is known that the links between pre-natal anxiety and schizophrenia are related only to stress that occurs in the first trimester (Khashan et al., 2008), whilst maternal anxiety experienced in the third trimester is more likely to cause offspring anxiety (O’Connor et al., 2002). Even more interestingly, there appear to be differential effects depending on the gender of the developing foetus, females more likely to develop anxiety, males more likely to be affected by attention, cognitive problems and aggressive tendencies! There is strong evidence for this in animal models and supportive evidence for this from human studies (Glover 2011; Glover & Hill, 2012)

The reason for these different gender outcomes has been thought about from an evolutionary perspective. Historically the female role in species survival in animals and humans has been to bear children and look after them, the male role has been to protect and provide resources. Different skills are required for these different roles. Thus, in a hostile environment, it pays for the mother to be fertile to ensure succession and hyper-vigilant to prey and threat. It pays for the father to go and explore new territory for food and shelter, to take risks to achieve this and to be aggressive enough to fight others for territory and food. In this context, the effect of stress in generating anxiety in females and cognitive impairment and aggression in males can be understood. Hey, in an Armageddon situation I think we would all want rough and tough Bruce Willis at our side not intellectual Stephen Fry.

In animal models it has also been found that stressed out female rats reach sexual maturity earlier, are sexually active earlier, have more offspring but invest less time in the care of each (Meaney, 2007). We have to remember we are talking about rats here, but in humans there is evidence that a harsh early environment (poverty, neglect, abuse) can lead to precocious puberty. You can draw any other rat-human parallels yourself.

The astute amongst you, might be complaining that this is all hogwash and that so many things might be confounding the picture. A confounder is something that can be related to both the purported cause and the outcome. The main ones affecting our current scenario are things like poverty, post-natal depression and maternal educational level. One could argue that a deprived, uneducated mother prone to depression is more likely to experience stress during pregnancy and more likely to have difficulty raising children, thereby causing the psychological deficits seen in their offspring in childhood and adolescence. In animal studies, this is easy to exclude, the new born pups or monkeys are cross fostered so that the mother stressed in pregnancy is replaced once the baby is born by an unstressed mother. Results remain. It is not possible to do this with humans.

In the majority of human studies, known and suspected confounders (social class, post-natal depression, maternal education to name a few) were measured and significant results remained even when these confounders were taken into account. What about the effect of genetics? It is possible to argue that a mother genetically predisposed to anxiety is likely to be anxious in pregnancy and to pass on anxiety genes thereby causing offspring to be anxious. You can see how hard it is to prove anything in science, yet clever research designs continue to come up to try and get to the answers. In a master-stroke of research design now possible due to the frequency of in-vitro fertilisation, Rice (2010) compared, in a cohort of IVF children, the association between prenatal stress and child outcome in those who were genetically related to the mother with those who were not (i.e. receiving egg donation). They found there was an association between mother’s stress in pregnancy and child’s symptoms of anxiety and conduct disorder even in the unrelated mothers.


How does this relate to you and me?

So, how to prevent anxiety in pregnancy? For me, I was smug reaching pregnancy having achieved a stable, loving relationship, stable financial and employment situation and having lived child-free life to the full. I felt I was ready to face pregnancy and motherhood in the best position that I could be in to avoid anxiety. There would have been nothing to stop a loved one being run over by a bus or being faced with infertility problems or illness but, at least the readily controllable variables were answered for.

Things can’t always go as planned though! Typical of most pregnant ladies, the thought of a new bald addition to the family somehow provokes the mental image of bald addition being placed into a beautiful, white cot with pressed linen sheets in a light and bright nursery attached to a south-facing home with wooden floors, modern furniture and period features. Hence in the first trimester of pregnancy Banker and I embarked on a 10 month process of flat hunting, flat offers, flat rejections, flat offer accepted, flat exchange of contracts, flat completion delay, eviction from rental and 2 weeks of homelessness, worldly goods in storage and 2 week enforced holiday in France to avoid sleeping on the street, flat completion, moving in, moving out, flat total remodelling and renovation, all of which no doubt sent the cortisol flying through my placenta!

Here biology and scientific literature come to the rescue again. Thankfully, like all natural miracles, the pregnant body seems to do all it can to protect itself and its prize. It is well known that in the third trimester of pregnancy and for a period post-natally the body dumbs itself right down (Henry & Rendell, 2007). Having for many years prized myself on my amazing memory and lauded it over my husband who seems to have been born with the happy disposition of the forgetful, I became just the same. Misplacing things left, right and centre, but instead of fretting and panicking, just sitting back and saying “Ah, sod it”. During my last week at work, I merrily typed away at a patient’s report only to re-read it to find that it was gobbledegook! Evolutionarily this dumbing down particularly affecting memory impairment is likely to protect against the harmful effects of third trimester anxiety, as well as to help block out the trauma of childbirth so that we become willing victims for another round!

Further, there was a caveat in the maternal anxiety literature! In a review of the literature, Vivette Glover (2011), a fellow North West London resident, describes studies selecting only well-off middle to upper class women in stable circumstances. They found that in this group mild stress in pregnancy had a beneficial influence on child outcome with better mental and physical development of the children and a similar trend for IQ. The suggestion is that in this group of women, a small amount of pre-natal stress may actually enhance foetal brain development. This inverted-U shaped dose-response effect is typical of anxiety and you will be familiar with the idea that a small amount of anxiety helps you sharpen your attention to perform on stage or in an exam, but too much anxiety can cripple your efforts. If Big Sis wins the Nobel Prize, I’ll be remembering to send a bottle of bubbly to my builders for the aptly timed “mild” stress!

References and Influences:

Beydoun H, Saftlas AF. Physical and mental health outcomes of prenatal maternal stress in human and animal studies: a review of recent evidence (2008). Paediatric and Perinatal Epidemiology, 22, 438–466.

Talge, N.M., Neal, C., Glover, V. and the Early Stress, Translational Research and Prevention Science Network: Fetal and Neonatal Experience on Child and Adolescent Mental Health (2007). Antenatal maternal stress and long-term effects on child neurodevelopment: how and why? Journal of Child Psychology and Psychiatry, 48, 245–261.

Van den Bergh, B.R.H., Mulder, E.J.H., Mennesa, M. & Glover, V. (2005). Antenatal maternal anxiety and stress and the neurobehavioural development of the fetus and child: links and possible mechanisms. A review. Neuroscience and Biobehavioral Reviews, 29, 237–258.

Berkowitz, G.S., Wolff, M.S., Janevic, T.M., Holzman,I.R., Yehuda, R., & Landrigan, P.J. (2003). The World Trade Center disaster and intrauterine growth restriction. Journal of the American Medical Association, 290, 595–596.

LaPlante, D. P., Barr, R.G., Brunet, A., Du Fort, G.G., Meaney, M.J., Saucier, J.F., Zelazo, P.R., & King, S. (2004). Stress during pregnancy affects general intellectual and language functioning in human toddlers. Pediatric Research, 56, 400–410.

Khashan, A.S., Abel, K.M., McNamee, R., Pedersen, M.G.,Webb, R.T., Baker, P.N., et al. (2008). Higher risk of offspring schizophrenia following antenatal maternal exposure to severe adverse life events. Archives of General Psychiatry, 65, 146–152.

O’Connor, T.G., Heron, J., Golding, J., Beveridge, M., & Glover, V. (2002b). Maternal antenatal anxiety and children’s behavioural/emotional problems at 4 years. Report from the Avon Longitudinal Study of Parents and Children. British Journal of Psychiatry, 180, 502–508.

Glover, V. (2011). Annual Research Review: Prenatal stress and the origins of psychopathology: an evolutionary perspective. Journal of Child Psychology and Psychiatry 52, p 356–367.

Glover, V. & Hill, J. (2012). Sex differences in the programming effects of prenatal stress on psychopathology and stress responses: An evolutionary perspective. Physiology & Behavior 106 (2012) 736–740.

Meaney, M.J. (2007). Environmental programming of phenotypic diversity in female reproductive strategies. Advances in Genetics, 59, 173–215.

Rice, F., Harold, G.T., Boivin, J., van den Bree, M., Hay, D.F., & Thapar, A. (2010). The links between prenatal stress and offspring development and psychopathology: Disentangling environmental and inherited influences. Psychological Medicine, 40, 335–345.

Henry, J.D. & Rendell, P.G. (2007). A review of the impact of pregnancy on memory function. Journal of clinical and experimental neuropsychology, 29 (8), 793–803.

[1] Interestingly, there appears to be an evolutionarily hard-wired biological predisposition to phobia development to things which are traditionally harmful. Thus, it is easy to induce a phobia for things like rodents, snakes and spiders but very difficult to induce a phobia to cars, guns and knives which are more likely to be a threat in the modern age.

[2] A dose-response effect is an effect whereby the greater dose of something purported to cause a particular effect, will cause a greater effect. For example, if sun exposure is linked to tanned skin, a dose response effect would mean that more sun exposure leads to a deeper tan. Finding a dose-response effect is good (but not necessarily definitive) evidence that a causal link exists.

Nurturing nature

glassesEveryone (I hope) recognises the existence of genes and their effects. Most people are happy to “believe” in genetic effect in hair colour, blood group and genetic medical disorders, but where “personality”, “intelligence” and “mental health”, come into it, most people prefer to see environmental causation. Part of the problem in selling genetic explanations is in the fear of “determinism”: the thought that your lot in life could be determined at birth and that human will and struggle are for nought. The funny thing is that “nurture” the proxy term for “environment” can also have its own form of determinism, with many people struggling to escape from the prison of their family and birth environments. Funnily enough, it is when things go wrong, when a child becomes “out of control”, that people flock to a genetic explanation, absolving themselves of responsibility. “They were born that way. It had nothing to do with our parenting.”

Outcome is clearly about both nature and nurture. What interests me is the interaction between genes and environments. It’s a wonder how the nature vs nurture debate has lasted so long, as the two are so intertwined. At the most basic level the success of a gene is purely based on its suitability for the environment. At a more complex level, a parent will give to their children both genes and environment, genes will seek out their own environments (e.g. a child with “intelligent genes” will ask to go to chess club), and evoke their own responses from the environment (a child with genes for physical attractiveness will generally evoke more favourable responses from others).

It is a misconception that you can have “good genes” and “bad genes”. Genes are like nature’s version of trial and error. A new combination is attempted at every conception, and the genes that are successful within an environment survive, the ones that don’t fall away. Thus the success of a particular gene is purely judged on environmental adaptation. A “good gene” in one environment may be a “bad gene” in another. Take genes that cause sickle cell. This is generally thought of as a “bad gene”, causing anaemia. However, in some parts of Africa, where Malaria is endemic, the sickle cell gene is a “good gene” as it is protective against malaria. This is palatable when talking about a medical condition, but the same applies for genetically determined personality traits.

Take aggression. Elements of aggression are genetically determined. It easier to think about dogs when talking about this: certain breeds of dog make for better security and attack dogs. No one would ever have a pug dog or poodle as a security dog. Yes, you can rear a poodle or pug dog to be aggressive certainly, but not as readily or to the same extent as an Alsatian or Pit Bull. There’s something in the genes. However, aggressive genes are not in themselves “bad genes”. In certain environments (the end of the world/ lost in a dark forest with wild animals surrounding you, a competitive job market), they may be the best genes ever.

Another reason for fear of genetic explanations is in the fear of genetic modification, gene selection and “tampering with nature”. You either feel it will end in a slippery slope to eugenics or you feel there is nothing that can be done with genetic predispositions and you just have to live with them. The thing is; it’s much simpler than that. In this day and age; we are able to cheat nature. My genetic predisposition to short sightedness has been environmentally sorted by living in a country with access to an optician. By all rights, had this not been the case, I would be dead by now, probably having gone to hug a grizzly bear that I mistook for my mother. The most common genetic predisposition in the world; that for having dark hair; is environmentally corrected around the world on a daily basis by bleach from a bottle.


Well, it strikes me that as parents, we are able to drastically manipulate our child’s environment, especially the early environment, which is thought to be one of the most important periods of environmental influence. This is not only by providing safety, books and toys, but exposure to language, music, models for good social interaction, peer group, selection of nursery,  primary and secondary school, and critically, love, warmth and understanding . By learning via observation about our children’s “genetically determined” personality traits, we are able to best shape their environments to suit their needs. All parents are doing this already off course, when you select your child’s nursery, primary school and secondary school, you are thinking not only about the values of the school you wish to impart on your child, but the attributes of your child and how they will fit into the school. It would be an oversight to send a small, intelligent boy with a love of learning and loathing for the outdoors to a school specialising in outdoor sport with a relaxed attitude to bullying, for instance. If your child has particular needs, for instance a learning difficulty, for all the medications and new age therapies; thinking hard about school and environmental placement is the most effective treatment.

A child with average genetic susceptibility to aggression can become very aggressive if brought up in an aggressive community. Equally, a child naturally predisposed to aggression can succeed perfectly well if the environment (parents, schools and society) show understanding and help shape the aggression so it is controlled and pro-social outlets found: competitive physical sport (though not biting other players), some occupations where controlled aggression is valued e.g. some businesses. A child naturally predisposed to aggression can only become a menace to society if parents, schools and societies allow it to be so.




How smoke exposure in pregnancy can cause aggressive kids



Wellies in summer are about as useful as aggression in Barnes


This is part 3 of the “How to improve the success of your kids before they are even born” blog series. See Part 1 and Part 2.

If folic acid is the Austin Powers of womb environment, then Dr Evil has got to be cigarette smoke. O.K., O.K., there are plenty of other bad guys obviously – thalidomide, heroin, alcohol. The reason I am casting cigarette smoke as the bad guy here is that whilst you have total control about exposure to the others, passive smoking is harder to control. The US Department of Health and Human Services (2006) estimated that more than 126 million non-smoking adults continue to be exposed to second-hand smoke in the US. Some of these millions are likely to be pregnant. Thank goodness for the U.K. law banning smoking in bars and restaurants. This was great for winter time, but having had both pregnancies through spring and summer, it was a real pain to anticipate a delightful al-fresco meal in the fresh air, only to find, given the laws prohibiting smokers from dining inside that all the outdoor tables at pubs and restaurants were over-run with smokers. Worse still, I found that friends would continue to light up in front of me in social situations when I was pregnant. Most of the time, I would alert them to smoking and pregnancy but this usually meant they moved a few paces away and tried to blow smoke in another direction with varying degrees of success. I’m not a smoking killjoy. I enjoyed cigarettes in my youth, and drinking in other people’s smoke used to bring back good memories, but when I became pregnant this changed and my mind would shout “TOXIN, TOXIN” if ever smoke touched my nasal hairs. Sometimes, not to cause a scene I just grinned and bore it, but images of damaged children would always run through my mind.

Most everyone knows that you shouldn’t smoke in pregnancy, but I’ll bet you didn’t know why? Studies have shown that there are over 4,000 chemicals in cigarette smoke and more than 40 of these are known to be linked with cancer (Thielen et al., 2008; US Department of Health and Human Services, 2010). Many of these chemicals, including nicotine, are able to cross the placenta into the foetus’s blood stream where, due to differing mother and baby physiology, concentrations can build up to higher levels in the foetus than in the mother (Lambers & Clark, 1996). Every time you have one, that’s two fags for the baby. There is evidence that links exposure to smoking in the womb to an increased risk of spontaneous abortion, pre-term delivery, and the baby going on to develop asthma, allergies, breathing problems and even cancer in later adult life. If you are a pregnancy smoker, you know all this and are as immune to this as being presented with a photo of a messed up smoker’s lung in the doctor’s surgery when they suggested you quit. What may influence you and what were my main concerns, were with the lesser known associations of smoking: with higher levels of aggression, conduct problems, attention problems, impulsivity, memory, speech and language and intelligence (Knopic 2012). It shouldn’t really sway you more, but put it this way, if your child develops cancer in adult life, it’s a long way off and is largely their problem to deal with. If your child is prone to aggression, that’s going to be your problem in a matter of months to years! If you did already know that, then I bet you didn’t know how cigarette smoke does this?

If you do then you are well ahead of the scientists! Scientists are still hard at work on this, but their current hypotheses surround the fascinating ideas around foetal programming and epigenetics. The theory of foetal programming is attributed to David Barker. David studied a group of mothers who were pregnant during the Dutch famine of 1944-1945 and followed up on the consequences of the children who were in utero during the famine. These mothers suffered malnutrition and stress, the children exposed to maternal starvation and stress were found to have lower birth-weight which is of no surprise. However, despite the end of the famine and a return to plentiful food supply, these children went on to have worse adult outcomes than children conceived just after the famine ended. These included cognitive deficits and higher likelihood of type 2 diabetes, heart problems and obesity. Barker’s theory is that there is a mechanism for Darwinian adaptation to environment occurring right there in our swollen abdomens that has probably been responsible for the success of our species. He postulated in the 1980s and 1990s that the developing foetus could take on information from the mother’s womb environment and use this to “forecast” the state of the environment into which it would be born. It is then able to prepare itself by adapting to be able to best survive the predicted environment (generate a predictive adaptive response); in much the same way that we might reach for the umbrella, coat and wellies on hearing a weather forecast for rain. Thus, if the developing foetus finds itself in an environment in which nutrients are scarce (such as the Dutch Famine) it thinks to itself “Bugger, I’m in for it when I get out, if my mother can’t find enough food to eat, there’ll be no damn food for me!” It therefore adapts (programmes) itself to be small and thrifty (conserve and use minimal resources) in order to be able to best survive the harsh environment it will face on birth.

Through this mechanism our ancestors lived to survive droughts and famines long enough to reproduce and eventually generate us. The foetuses that did not adapt themselves in this way would have died in infancy and childhood not being resourceful enough in their physiology to withstand periods of deprivation. The problem occurs if the forecast is wrong as adaptations made at these early stages of development are generally permanent. In the Dutch famine group, conditions improved after 1945 and food became plentiful again. The small and thrifty babies turned into children and adults that continued to store everything they ate and basically became more obese and prone to obesity related diseases, compared to children from similar backgrounds born just a year or so later. This is the fool in his heavy overcoat, wellies and umbrella at the beach in 30 degree heat cursing Michael Fish’s dodgy weather report.

How the foetus is able to use womb environment information to affect changes in its development is thought to be by epigenetic effects. In essence, epigenetics is the study of which sections of DNA gets expressed. In my analogy of DNA as a large manual for human construction, epigenetics is the study of the post-it notes put into the manual to instruct the builder which instructions to follow and which to ignore. Scientists have discovered several ways in which these post-it notes can be inserted, one of which is by a process called “DNA methylation”. Smoking has been shown to affect this process and others implicated in epigenetics which activate changes in the placenta (which can then affect the development of the foetus) and foetal development directly (Knopic, 2012). Epigenetic changes can also be inherited and can continue to influence at least 2 generations of descendants (at least in insects-Matthews & Philips 2010), thus what you do in pregnancy now may not only affect your children, but also your grandchildren!

A foetus exposed to high levels of toxins (like cigarette smoke) might prepare itself by bolstering its immune defences. On being born to a toxin free environment, the hypersensitive immune system gives rise to asthma and allergic reactions, which are essentially immune responses to normal everyday surroundings. It is harder to understand the adaptive nature of the psychological associations of prenatal exposure to cigarette smoking (aggression, impulsivity), but it makes sense that if toxins are part of what can be described as a “hostile” environment, that the newborn baby and subsequent child should be prepared to look out for danger and fight its way in the world. Aggression, hypervigilence and risk-taking behaviour would be beneficial traits to aid survival of a toddler in an Armageddon situation, but probably not so beneficial in a 3-bed semi in Barnes.

I went to a Justin Timberlake concert when I was pregnant with Big Sis and she came out ready to dance! Does that count?


US Department of Health and Human Services. (2006). The health consequences of involuntary exposure to tobacco smoke: A report of the surgeon general. Atlanta, GA: Centers for Disease Control and Prevention.

Thielen, A., Klus, H., & Muller, L. (2008). Tobacco smoke: unraveling a controversial subject. Experimental and Toxicologic Pathology, 60, 141–156.

US Department of Health and Human Services. (2010). A report of the surgeon general: How tobacco smoke causes disease: What it means to you. Atlanta, GA: Centers for Disease Control and Prevention.

Lambers, D. S., & Clark, K. E. (1996). The maternal and fetal physiologic effects of nicotine. Seminars in Perinatology, 20, 115–126.

Knopic, V.S., Maccani, M.A., Francazio, S. & McGeary, J.E. (2012). The epigenetics of maternal cigarette smoking during pregnancy and effects on child development. Development and Psychopathology 24 (2012), 1377–1390.

Matthews, S.G., & Phillips, D.I. (2010). Minireview: Transgenerational inheritance of the stress response: A new frontier in stress research. Endocrinology, 151, 7–13.


How to improve your child’s success before they are even born: part 1

The egg and sperm race

I am sure most parents will know that the human race begins with the egg and sperm. The egg contains information coded in DNA from the mother as well as a functioning cell with battery and starter pack to kick start reproduction. The much smaller sperm contains information coded in DNA from the father as well as a whippy tail to get it swimming to deliver the information to the egg.

What is important is the genetic information coded in the DNA contained in egg and sperm. This is the basis of biological relatedness. What is this information and where does it come from? Your DNA (deoxyribonucleic acid) is basically the instruction manual of how to make you. Every single cell in your body: your liver cell, your blood cell, your skin cell contains a full set of your DNA. The only cells that do not contain a full set of instructions (DNA) are the egg and sperm. They each only contain half. Busy in the germ lines of female ovaries and male testes are the egg and sperm factories. Here, the DNA dances about a bit, and gets chopped in half at random and packaged up into eggs in the ovary and sperm in the testes. It is at conception that the sperm meets egg story finishes and as in the Spice Girls song, “two become one” literally. A novel instruction manual is made for the new individual based on information from father and mother.

So what does this have to do with parenting? Well, whilst environment and upbringing has significant impact on how someone turns out, there is no denying the existence of genetic effects. It doesn’t take a clever-clogs to work out that identical twins (who share 100% DNA and the same womb at the same time (scientifically referred to as gestational environment)) are a lot more similar than non-identical twins (who share gestational environment but only 50% of DNA), for a start, non-identical twins can be different genders! Their genetic relatedness to each other is no different from any other brother or sister. It is consistently backed up in scientific literature involving twin and adoption research over a range of disorders (learning difficulty, ADHD, schizophrenia, depression, anxiety, autism as well as physical conditions), that monozygotic (identical) twins are more similar to each other than di-zygotic twins (non-identical). This is true even if the twins are raised apart, thereby disentangling the tendency of society to treat identical twins more similarly. This is good evidence for genetic effects and no one really bothers to argue this anymore.

Where debate continues, is on the matter of more or less of environment or genetics, but I am quite happy to fence sit at 50% of each. In reality, research is moving towards relative percentages differing from person to person with nature and nurture interacting in a multitude of ways making the simplistic nature versus nurture argument completely obsolete. The percentages don’t matter, what matters is that genes are an important contributor and it is a contributor that we have knowledge and control over. When “control over genes” is mentioned people automatically think about eugenics, gene therapy, genetic engineering and designer babies, which is expensive, not widely available and ethically controversial. They tend to ignore the easiest and most widely used method of gene selection.

Genetics has merely given evidence to what people already knew: that “the apple doesn’t fall far from the tree”. For time immemorial dog and horse breeders have been selectively mating animals to produce favourable traits in their progeny; long before IVF and the debate on designer babies. In humans the basis of attraction has evolved to envelope the physical traits of health and success (tall height, glowing skin, good musculature) and Eastern and Western societies alike have chosen suitors based on family background to promote the likelihood of healthy and successful succession based on past record of ‘genetic’ performance (what their family is like). These days there is more emphasis on personality and intelligence than health and virility, but the same still holds true. If you don’t like the personality or intelligence level of your partner and can’t stand any members of his/ her family, there is a good chance that you might not ‘like’ your child. This will be truer still if you also do not like yourself or any members of your own family!

This might sound un-PC, unromantic and overly pragmatic, but with my behavioural geneticist hat on, a major step in helping parenting is finding the right spouse. Not only to love and support you throughout your life, but also to provide children with easy temperament and a personality that won’t jar with yours! This is important as unlike a lover or a partner, who you can divorce and be rid of (society and religion permitting), your children are yours and your responsibility until they are 18 years old at least, whether you like it or not!

Thankfully it is not as hard as it sounds to find compatible stock, because presumably most people seek to find partners that they actually like as well as love. The “like” part is important here as whereas a good dose of physical attraction, athleticism, sexual prowess and general lusty desirability can save any marriage, these traits are no good in helping you “like” your child, and if it does, then you probably need professional help as incest is illegal in most countries. If you would enjoy 18 years of your own or your partner’s non-sexual company, then you have at least the best chance in genetic terms of liking your children. For women, given that conception is now available by IVF from sperm donation, it is interesting to consider whether one would select the same profile for a sperm donor (thus providing you with children of biological relatedness) as one would consider for a spouse (sperm donor plus husband and father). An aggressive, dominating, powerful alpha-male type might be an exciting conquest and offer physical protection as a partner, but an aggressive, dominating five year old son? That’s a recipe for grey hair! Personally, for me, whilst there would be a broad overlap in the husband/ son characteristics wish-list, the two would be slightly different. Whilst a husband who called his mother every day and wanted to visit his mother weekly would be abhorrent as a husband, this would sound like a pretty cool son!

During my training, I helped conduct genetic counselling assessments for couples where there was a history of autism in the family. Autism is a disorder of social interaction and communication with a likely genetic basis, the common form is thought to be a polygenic disorder, whereby risk is conferred by multiple as-yet-unidentified genes. Most heritable traits, such as intelligence, aggression and attention are also likely to be due to multiple genes in combination. The genetic counselling assessment involves taking an extremely thorough family history for symptoms of autism and its broader spectrum, going back through as many generations as there is information. The way it works is that the more “genetic loading” there is in the family (i.e. the more family members with the disorder or traits), and the closer they are in relation to the parents, (i.e. the greater likelihood of shared genetic material), the greater the statistical probability that the couple in question will have a child with autism. Parents and siblings share 50% of genes with any one child. Grandparents, aunts, uncles, half-siblings share 25% genes, great-grandparents and cousins share 12.5% genes and so on. This family history is important as a person can be unaffected but still carry risk genes for a particular trait or disorder if they have high “genetic loading”. If you extrapolate this to other potentially genetically determined traits, you can see the importance of assessing your spouses’ family in determining outcome for your children. If your partner is the most wonderful person but he has the most annoying brother who you can’t stand, there is a possibility that your child will inherit this “annoying” gene that was being carried but not expressed in your partner. In order to limit the likelihood that your child will be genetically “annoying”, then neither you nor your spouse or any member of your families should be annoying. Of course, they can still develop propensity to be annoying via environmental factors! Sometimes two exceptionally bright parents produce offspring of average intelligence leading to confusion and disappointment, when in actuality looking at the broader family; it may be easy to tell that the parents themselves were exceptions to the prevalent genetic loading.

For me, I was lucky in that the man I fell in love with and subsequently chose to marry and be the father of my children is a sociable and intelligent man with easy temperament, low aggression and blind optimism. Although it is often infuriating (he has a penchant to leave windows open when going out because the chance of burglary in London is low in his mind set), what I have gained from his DNA is a daughter who is relaxed and easy going. On breaking her left leg, after the initial pain had settled, she never complained or moaned once and would cheerfully state “Well, my right leg is O.K”! An older colleague of mine stated that she could never hate her ex-husband despite his affair and the breakdown of their marriage as his genes gave her two wonderful, intelligent and compassionate children.

Genetic consideration should also be given to ground expectation of your children’s ability.  It’s unlikely that you can ‘inherit’ ability for needlepoint. What is heritable is “visual acuity”, “fine motor skills”, “ability to concentrate and pay attention to detail”, “low sensation seeking”; traits which would make it possible given environmental exposure, passion and encouragement to excel at needlepoint. If neither you, any member of your family or your partner and his family have anyone with any of these core abilities, your dreams for spawning the next “World Needlepoint Champion” aren’t impossible, but the odds are stacked against you as genetically, you would be banking on a genetic mutation to deliver the goods. Environmentally, you can still make good headway and environment can definitely conquer much of genetic disadvantage, but could it conquer others with genetic and environmental advantage? Unlikely. Whilst I don’t believe in ruling out potential in children, I have enough clinical experience to see that unrealistic expectations are really corrosive to the child’s self-esteem. Parents who have overly aided and abetted their children into academically competitive schools only to confront the child prematurely with the limitations of their ability and press the self-destruct button, children with learning difficulties made to remain in mainstream school to struggle academically and socially as parents are unwilling to face up to reality and accept their children for who they are. Knowledge about genetic background can help as fore-warned is fore-armed. What, if any, action is to be taken is up to the individual to decide, and family histories and traits are merely a very rough guide rather than an oracle.

Different people will respond differently. In the genetic counselling for autism clinic, when we relayed the statistical probabilities of having a child affected by autism back to families, the disparity in reactions was great. Despite relaying the same low statistical probability (less than 5%) back to two couples with similar genetic loading, one felt happy to ignore the very low level risk, but in the other, the woman decided to divorce her husband (where the family history lay) rather than procreate with him and run any risk of having a child with autism.

In my case, I warned my husband from the outset that should he be hoping for a brood of NBA contenders or 100m sprinters then he had better think again about his choice of wife; height and fast twitch muscle fibres being rather lacking in my family. In his turn, I was to wipe singing in tune from my list of aspirations for our children. I think together we might have an unstoppable force for card games and scrabble.