The only 'choice' for religious maniac parents is between having their 15 year old daughters educated about sex by qualified teachers, or by children a year older than them. Or simply by the practical method, up to and including the highest level - or childbirth, as it's also known.
The argument in favour of preserving sexual ignorance in children is that 'children are not the property of the state', or similar nonsense. Whereas they ARE the 'property' of their parents? Since when? This is typical of the psychotically individualistic attitude of those who to whom consumer 'choice' means 'freedom'. In fact, it is the darkest prison. The fact that they can refer to their children as cattle means they are not qualified to make any choices regarding their welfare.
For primary school children denied professional tutelage because of their parents' paranoia and neuroses, the other source of sex education is, of course, internet porn. This perverted veiw of sex might be even worse than no education at all, especially as far as girls are concerned.
Those who would exclude the state from all influence on education sing a different tune when they are told about a single mother of three claiming benefits and jumping the housing queue. Who's fault is that? Normally The Parents.
Either way, the state has an obligation to take decisions which will benefit the majority. Hordes of sexually-malfunctioning teenagers, spawning unintended dysfunctional state-dependent families onto the taxpayer's bounty is in nobody's interest.
That's why we have an education system in the first place. I'm sure the discombobulated genteel classes think that 'the whole theory of education is radically unsound' but luckily, they also prove that 'in Britain, education has no effect whatever.'