Legislating around sex is always difficult, and reconfiguring the law on sexual offences involving children was always going to be a complex and controversial task. It is also a necessary one because currently Scotland relies on a mass of statute and common law dating back to Victorian times that sends out confusing messages. We need the law to protect our children from harm and exploitation. Sexual assault and any sexual intercourse involving an element of coercion should be a criminal offence, regardless of the age of the offender. And any form of sexual activity below the age of 13 should be regarded as inappropriate.

There is a broad consensus on these issues. But what if we are dealing with two youngsters, aged 14 or 15, involved in a consensual relationship? At present the law deals with them unequally. Though it rarely happens, the boy can be charged with rape and, theoretically, end up with his name on the sex offenders' register. Is this fair in an age when girls reach puberty around two years earlier than did their grandmothers' generation? The fact that it is largely hypothetical is no excuse for inaction.

Under recommendations from the Scottish Law Commission, consensual sex for 13-year-olds to 15-year-olds would be effectively decriminalised, though either party could be referred to the Children's Panel if there was cause for concern. This proposal is already raising eyebrows among those who argue that it virtually amounts to lowering the age of consent. (Technically, this is incorrect because anyone 16 or over would still be charged with the rape or sexual assault of someone under 16, regardless of whether there was consent.) As Children's Commissioner Kathleen Marshall argues, it is perverse to punish children using laws intended to protect them. Vulnerable children need education and support, not criminal records. The danger is that decriminalising sex between older children risks sending the wrong message.

In a country with some of the highest levels of teenage pregnancy and sexually transmitted disease in the world, this may suggest that sex between young teenagers is an acceptable norm. There is an obvious parallel with the downgrading of cannabis. If there is a lesson from that debacle, it is that such changes can be damaging unless accompanied by a strong, properly supported, public health campaign. There must be lingering doubt about the issue of consent. If the law assumes that children under 13 are incapable of giving consent to sex, how can we assume that on their 13th birthdays they suddenly acquire that capability?

Defenders of the reform will argue that the SLC's proposal means that girls in this situation could be referred to the Children's Panel on welfare grounds. But before the Scottish Government goes ahead with this change, ministers must be convinced that what may look like consensual relationships do not contain elements of coercive peer pressure or insidious manipulation. Children mature at different speeds. We need a legal framework that protects the vulnerable without inhibiting the snogging and cuddling that constitutes normal teenage behaviour.