The things your children do that you can blame on their genes

“I blame the parents” has been a common mantra of pearl-clutching pundits over the years, the implication being that if only those lazy, overeating and obnoxious children had been brought up in a “decent” environment by parents who actually cared, then society would be a lot better for it.

That may soon be a thing of the past, however. In the nature vs nurture debate, science has picked a side: genetics has a much greater influence over a child’s character and behaviour than any other factor.

A new study has found even fussy eating among children – the bane of many parents – is less determined by making sure little Timmy is exposed to greens and pulses from infancy, and more to do with genetic variation. The researchers from University College London (UCL) and the University of Leeds describe how fussy eating habits were more similar among identical twins than non-identical twins (almost all similar studies use twins), showing that genetics is a much bigger factor in the differences between children’s pickiness than once assumed.

“The reason why some children are quite ‘finicky’ and others are more adventurous is largely down to genetic differences between children rather than parenting styles,” said Professor Clare Llewellyn on the Today programme.

Heritability – how much of the differences between individuals can be explained by their inherited DNA differences – went mainstream after the publication of Robert Plomin’s book, Blueprint: How DNA Makes Us Who We Are in 2018. “Genetics explains more of the psychological differences between us than anything else put together.”

Plomin finds that heritability accounts for 50 per cent of the psychological differences between us, from personality to mental abilities. But he also argues that the assumption the other half is directly related to environment is false. “Genetic influence slips in [to factors such as parenting and life events] because these are not pure measures of the environment ‘out there’ independent of us and our behaviour… We select, modify and even create our experiences in part on the basis of our genetic propensities.”

Public perception appears out of sync with these revelations. In a 2017 survey of 5,000 young Britons for Plomin’s book, 30 per cent thought reading ability was determined by genetic factors, whereas scientists believe it is 60 per cent. That does beg the question, would you bother to read to your children at bedtime if you knew they were genetically predisposed against reading or would you fight the DNA even harder to compensate?

Similarly, 33 per cent thought spatial ability is down to inherited differences, whereas the actual figure is 70 per cent. Even with seemingly obvious genetic factors such as eye colour, public perception was off, with only 77 percent believing this was down to inherited traits, whereas the true figure was 96 per cent. Unless you share the optimism of Plomin, you’d be forgiven for thinking this removes a lot of agency from parenting. Why bother, you may ask?

If your little boy is a clumsy oaf who regularly smashes glasses and plates or embarrasses you in department stores, you can at least rest easy knowing that there’s nothing you can do about it. The study showed school achievement was assumed to be only 29 per cent down to genetics, though the science says it is more like 60 per cent. So don’t beat yourself up when your little ones come home with a measly “meets the expected standard” mark in their SATs. They probably did all they could with the genes you gave them.

Plomin says modern genetics give us “Power to predict our psychological strengths and weaknesses from birth” and that DNA is a “fortune teller”. Access to thousands of variations in our DNA can produce a “polygenic score”, indicating the likelihood of a range of mental health conditions such as depression or schizophrenia and our predisposition to traits such as obesity. “I do not know of a single psychological trait that does not show genetic influence.”

Fascination with the nature vs nurture debate goes back a long way. In the 13th century, the Holy Roman Emperor Frederick II put two babies into prison cells without any contact to see if they would grow up speaking Latin, Greek or Hebrew. Spoiler alert: they died.

In theory society could and should adapt to fit their genetic make-up. “Heritability can be seen as an index of opportunity and meritocracy,” as Plomin says.

Parents therefore face a choice of whether to “accept” the inevitability of their children’s DNA or to work against it. The research can lead to the conclusion that the behaviour of children, including mental health concerns or risk-factors such as addiction, can in theory be identified and understood better. The grey area comes in the reaction to such a diagnosis and how big a role environment then plays in any treatment. How much of a person’s character and even behaviour might one day be considered a fait accompli?

This all has overtones of Calvinist predestination theory, whereby God’s omniscience and omnipotence meant the souls of those to be saved (or in “double predestination”, damned) were determined, unalterably, from the moment of creation. If your loveable rugrat shows no interest in learning the violin, as you had desperately wanted, would it be better to keep paying for the lessons in the hope they learn to love it or should you just abandon it on the basis that they are genetically predestined to hate classical music? Gene theory suggests you should save your money. Especially as, 16 years ago, researchers thought there might even be such a thing as a “hobby gene”, following a survey of more than 2,000 British adults that suggested people inherited their ancestor’s hobbies, be it acting or stamp collecting.

But perhaps there it’s not quite time for a total surrender to genetic “nativism”. Dr Saul McLeod of the University of Manchester writes that certain genes react or interact with the environment, highlighting that “that genetic predispositions and environmental factors contribute to personality development, and their interaction is complex and multifaceted.”

This is commonly found with mental health, where individuals inherit a genetic predisposition to a disorder such as depression, but it is often activated or exacerbated by environmental factors or events. McLeod also writes, “The nature vs nurture debate is outdated – both play key roles.

Whatever lies in the future, if your child refuses to eat broccoli or keeps hitting the other kids in nursery, then you can either blame yourself for having dodgy genes or blame your parents for passing the dodgy genes on to you.

So when Philip Larkin wrote “They f--- you up, your mum and dad. They may not mean to, but they do. They fill you with the faults they had and add some extra, just for you”, it turns out he wasn’t just anecdotally correct, but scientifically correct too.