I wonder where these children get their language and knowledge of such adult issues from?
Rarely from TV or the media - more often than not it comes from parents, older siblings and from what kids hear and talk about in the playground or out in the street. It's rather like nits - you only need one kid to bring it into the school and pretty soon it'll be going around the place like wildfire.
As far as the DVDs go, these resources are ultimate only as good as the amount of time and effort that teachers put into using them and while sex and relationships education remains an optional extra on the curriculum, it will be difficult to get any real consistancy across schools.
This is where parents can make a positive difference. Most schools run a preview session before they use the two programmes on the DVD that deal specifically with sex and reproduction and that's really the time for parents to ask questions about how the DVD will be used in practice and push them if they feel that maybe they aren't giving enough attention to issues of safety and self-respect - although, to be fair to C4, self-respect is an ongoing theme throughout the whole DVD even if its not always addressed directly.
All schools that do provide SRE are required to publish their curriculum in full - some make it available via the school website - and I'd certain advise all parents to contact their school and ask for a copy of the curriculum if they've even the slightest concerns about the possible content or tone of the lessons.
Actually, conception rates for under 16s stabilised at the beginning of the 1990s at around 8 conception per 1000 young women and have broadly speaking been only a downward trend since 2000 - this years figure are 20% down on 2000. Birth rates have fallen slightly faster, largely because a higher percentage of teenagers opt to have an abortion these days, and the better educated a teenager is, the more likely they are to choose to have an abortion in order to stay on at school/college and complete their education. Where conceotion rates have risen in the last 20 years (1996/7 & 2006) it has always followed a sizeable health scare in the press over the safety of oral contraceptives - overall conception rates are pretty sensitive to the kind of health information that's being put into the public domain by the media.
STD rates for under 16s are, by and large, measured in single figure rates per 10,000 and 100,000 teenagers, depending on which one you're talking about. For syphilis, your looking at rates of between 1 and 8 cases per million teenagers every year. The only STD to show any significant increase in recorded incidence rates over the last decade is chlamydia and that largely because of the introduction of a new and much more effective test for the disease in the late 90's and the introduction of a screening programme in 2003. Disease rates always go up when you start actively screening for them, whether its an STD or breast cancer you're looking for.
As for sexual assaults, the British Crime Survey indicates that the current trend is downwards and the Police Recorded Crime figures show that more women are coming forward to report offences than used to be the case, but its still difficult to get fully reliable figures on this and the figures that are available can be difficult to interpret and work with, particularly when it comes to repeat victimisation in the family home.
I crunched a few numbers late last year and somewhat shocking discovered that anything up to a third of rape victims every year are likely to have been raped more than once, almost always within the context of domestic violence. That's around 20,000 women a year, which really doesn't bear thinking about.
I've personally blogged a lot of this material over the last 2-3 years and as I know that there's at least one staffer at Mumsnet who knows who I am from the blogs I write for, if anyone wants to get in touch with me directly using the email address on my profile, I'd be more than happy to put together a compendium of statistical information for Mumsnet showing what the real trends are for teenage conceptions, births, STIs and sexual offence rates.