So rather than roll over those subjects again:

In an ideal world I'd have to hand the statistics about some European approaches to sex education, which starts well before puberty and has, as its end result, lower teen pregnancy rates, later age of first sexual contact, and so on, and I'd be able to lay them out in that cool-headed rational way that is how one's supposed to act in order to be Convincing in this culture.
Or I could just dig out my Blogging for Sex Education Day post and emotive appendix and wave them around again like a bloody shirt. Possibly with an "As a mother of a baby girl..." attached to start hitting those buttons as hard as I can.
But, y'know, as a mother of a baby girl, the Hughes-and-Brookses of the world terrify me. They terrify me because they wish to make equipping Little Foot with what she will need to navigate the world in reasonable safety a crime, if not literally, at least socially: they want the concept of frank discussion about sexuality to be, if it exists at all, constrained to those above legal majority, keeping the youth vulnerable, exploitable, ignorant.
I mean, I'm familiar with this sort of thing, this idea that children are 'innocent', which is a code word for 'unsexual', and that they will be tainted by knowledge.
I've run into it in homophobic discourse - because straight people never realise they're attracted to MOTOS before puberty, so gay people who figure that sort of thing out must be inappropriately sexualised. I have a hobby of popping into those discussions to note that I had my first crush when I was seven or so, and recognised it at the time as "something that has to do with grownup things like getting married", and it manifested as - among other ways - wanting to touch the target of my affections which, being in elementary school, involved defeating him in a wrestling match at a friend's birthday party. These people remain wilfully ignorant of the way that hairpulling and teasing get labelled as "puppy love" when the children involved are of different apparent sexes, making it redundant for people for whom that sort of thing is actually the early and inchoate manifestations of sexuality to realise that hey, they're straight!
... those were some very long and complicated sentences. Anyway!
Once, when I was pointing out that I was aware of parts of my sexuality when I was pre-pubescent - that I was formulating my taste in boys from the age of seven, say, I don't think I'd even gotten into the definite awareness of some level of kink by the age of twelve - I got told that I was providing justifications for pedophiles. That self-awareness as someone who was formulating an understanding about "grownup relationship things" and how I felt about having them someday was some kind of mitigating factor that could excuse sexual abuse. That even acknowledging child-appropriate sexuality in a prepubescent was carte blanche for people to fuck children.
I can tell from the way I repeat that and rephrase it over and over that I go all fugue-y and kind of triggery about it.
Children are keen observers of the world, perhaps especially the world of adult social dynamics, because they have to relate themselves to that world in order to survive. A keen state of vulnerability means that understanding the systems of social interaction is a vital skill. (This, tangentially, strikes me as one of the reasons ASD can be so disabling.) Expecting that children will not be piecing together understandings of sexuality from what they observe is flatly ludicrous: even the ones who are not growing up in a household with adults who are in a romantic/sexual relationship of some sort will have friends with married parents, or single parents who are dating, or whatever else. They will see people with relationships on television, or watch a Disney movie and observe how this year's Princess gets her Prince. And they will find themselves drawn to explore things themselves: whether it's "if I touch this I like how it feels" or "That person there makes me feel happy and I want to be near them" or something else altogether in that complex of things.
We cannot cannot cannot dissociate children from an awareness of how what's in their heads relates to the adult world. And sexuality does not suddenly spring into existence from nothing at puberty, at age of consent, at legal majority, at an age where one is old enough to drink, no matter how much the rhetoric would like it to.
And I'm writing about children, because I have a child and I have to work through how to equip her with knowledge from age-appropriate ground up - which doesn't even touch on the vileness of equating teenagers who might be attending one of maymay's unconferences with my nine-month-old child in terms of what sort of sexuality discussion might be appropriate for them.
But this is a culture in which carrying condoms in order to be a responsible driver for one's sexuality frequently gets taken as being oversexed, slutty, indiscriminate, bad, and thus unrapeable, because sex isn't a topic for discussion; sex is something magical that happens from beyond and carries you away. Being frank, real, knowledgeable, aware, making deliberate choices: these are all the sorts of things that destroy 'innocence' and thus make a person guilty.