DEPENDING on where their children attend school, parents will have been shocked or delighted recently to hear an American geneticist claim that sending your child to a fee-paying establishment will not make the slightest difference to their academic results.

In a talk at Hay-on-Wye book festival, Robert Plomin, professor of behavioural genetics at King’s College London, explained that the results of 30 years of studying identical twins – outlined in his book Blueprint: How DNA Makes Us Who We Are – showed that places like Eton “don’t add anything” to a pupil’s educational achievement. His field of expertise, known as “hereditarian” science, was for decades shunned because of the appalling use to which theories of supposedly inherent racial difference had previously been put. To the ranks of disbelievers can probably now be added those cash-strapped parents who have sacrificed holidays, cars and clothes to pay eye-watering fees for their kids.

Until lately, environmental factors have been seen as the main factor in a person’s success or failure. However, Plomin persuasively argues that a child’s future is determined 50 per cent by their genes. Environment also accounts for 50 per cent, but according to his research, an individual’s response to this is largely a product of their genetic heritage. In short, our parents have a lot to answer for.

Yet while Plomin is adamant that it’s a pupil’s background that determines their exam results, he is also aware that choosing a private school is usually about much more than winning top grades. Fettes or Gordonstoun, Roedean or Harrow are seen as exclusive institutions where sons and daughters will meet the right class of people and – as importantly – not have to mingle with the wrong. Long after they have left the dorm and playing fields, these old chums will form a network whose efficacy in helping them up the greasy pole is affirmed by the front benches at Westminster.

As Plomin writes of his conclusions, “I hope it will help parents who cannot afford to pay for private schooling or move house to know that it doesn’t make much of a difference in children’s school achievement.” Clearly he recognises the financial dilemma facing those, not in the first rank of wealth, who want their kids to have the best possible start in life and think it’s worth almost bankrupting themselves to put them through the elite system. If his evidence of the superiority of nature over nurture is right, then it rebuts the age-old belief that money solves every problem, and that those born on the cusp of an overdraft are on the back foot from day one.

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Raised as I was in a family of teachers convinced that the state sector’s better-qualified staff offered a finer education, I was, you might say, indoctrinated about the deficiencies of fee-paying establishments from an early age. The opening pages of Evelyn Waugh’s The Ordeal of Gilbert Pinfold merely confirmed that view, although in recent years I’ve had to acknowledge that private education has improved considerably since I last dipped into an inkwell.

Yet the most important message to take from Plomin’s work is not that any school will serve its educational purpose. Rather, it is that responsibility for a child’s intellectual capabilities lies with parents, not teachers. Home is where the future lies. For years now, teachers, be they state sector or private, have increasingly been expected to take on the roles of nanny and counsellor, nutritionist, health advisor and social worker, not to mention become expert in conflict resolution. All this as well as their bread and butter task as educator.

When a child does not excel, parents demand to know why. The blame for poor results or under-performance is too often laid at the teacher’s door, when mum and dad should instead be looking into a mirror. This is not to say that every teacher is above reproach. But it is to suggest that on balance, parents should ask not what school can do for their child but what they can do for their child – and have already done, through no virtue or neglect on their part.

Money aside, on the question of state v private education, there now seems a simple distinction. Private institutions offer a one-stop shop, in which extracurricular activities are gathered under a single umbrella. In contrast, many pupils at ordinary schools are like popcorn in a microwave, bouncing from one out-of-hours diversion to another, be it football or ballet, violin or swimming lessons, Rainbow Club or Scouts.

Thanks to these myriad options, the distinctiveness of fee-paying schools is being whittled away. In addition, children at after-class events are mingling with a far wider group than could be found in private establishments. As a result, the private sector is in more danger of appearing narrow and restrictive than elitist.

That, of course, is a separate discussion. For the moment, Plomin’s results should simply help calm the angst that blights so many parents’ lives. If nothing else, they offer a reason to relax a little, and allow nature to run its course.