THERE was a fascinating report published recently about teenage brains. Jay Giedd at the American National Institute of Mental Health discovered in doing scans of young people, that their brains are still “under construction” — sometimes up to the age of 25. The human brain matures gradually, and the prefrontal cortex dealing with judgment is not properly formed until the twenties. Because of this immaturity of the front part of the brain, teenagers are naturally inclined to reckless and risky behaviour.

The implications of this finding surely have direct relevance for sex education. Sex educators often argue for more “choice” and an ever earlier start to sex education to halt the curve of early-teenage pregnancies. But it is clear from Dr Giedd’s study that young teenagers cannot always handle “choices” because their brains are in such a state of formation that “choice” may be translated as an invitation to risk-taking.

The theme is illustrated by the latest findings about early teenage abortion. The number of girls aged 14 and under having a termination of pregnancy has just exceeded 1,000 a year for England and Wales. The Pregnancy Advisory Service which performs many of these abortions on the under-15s says that “abortion can be a solution” for a 14-year-old’s pregnancy. Yes, it can be: but the better solution would be an expectation of care, protection and supervision to prevent such pregnancies being risked in the first place.

More “information” about sex education and contraception has not, so far, achieved this aim. This is not because young teenagers are bad, wilful or irresponsible: it is because of the half-baked state of their brains which may interpret “choice” as an exciting stimulus to reckless choices and the thrill of the risk.

Dr Giedd’s findings can be applied to drugs. Because teenage brains are immature, cannabis — which older people can sometimes use without harm — has a much higher likelihood of inducing psychotic episodes among under-16s. It is not kind to be laid back about this.

Teenagers can be intellectually brilliant in some spheres, and they have often been remarkably brave — teenage soldiers are recklessly courageous — precisely because of this risk-taking element in the composition of their brains. But it is cruel to expose them to neutral “choices” in sex education rather than protecting them from their mental immaturity.