“When did you lose your virginity?”

The presenter thrust her microphone into my face and waited. I was so taken aback that I answered, more or less truthfully. But that wasn’t enough. “So,” she asked conspiratorially. “Did you stack `em up at university?”

This, according to Channel 4, is the “open” and “ambitious” sex education debate that this country needs. I had been invited, as the TES reporter on sex education, to take part in a studio discussion for The Sex Education Show, a six-part series that began this week.

I went along because I believe the first step to effective sex education is open and honest debate among adults. What I discovered was that, as far as Channel 4 was concerned, “open and honest” translates as Carry On-style nudge-nudge, wink-winkery.

We began with contraception. The presenter, Anna Richardson (of Supersize vs Superskinny fame), opened by comparing the female condom with “shagging a crisp packet”. Had I been a teenager considering contraceptive options, I would be striking one off the list now.

She then spent five minutes rhapsodising about her fitted diaphragm being significantly smaller than average. Size does matter, apparently. Another one off the list.

We moved on to abortion. A mini-skirted 21-year-old talked about losing her virginity at 13 and having an abortion at 16. Then she talked about her fondness for sex parties and recreational sex. Nearby, an equally young, equally mini-skirted woman broke down as she recounted her abortion. She had been on the pill when she fell pregnant: the 1 per cent exception that proves the 99-per-cent-effective rule.

The message was clear. Two types of people have abortions: heartless slappers and unfortunate innocents.

In fact, the choice of panel members made me wonder how many stereotypes the programme really wanted to shatter. While the men were doctors, health workers and streetwise students, the female “sexperts” included a lap- dancing escort and a Penthouse writer.

Now, call me picky, but prostitutes - for that is what escorts are - and porn writers specialise in objectification. Neither is concerned with an honest, mutual expression of affection, based on trust and respect.

But this wasn’t what Channel 4 wanted to hear. When a sex therapist suggested that it would be wise, between recreational sex sessions, to consider the cost to your emotional life, the audience rounded on her. “You don’t like people being happy,” one man yelled. “Yeah,” said another. “It deprives you of clients.”

Yes. Women, from their teenage years onwards, want to fulfil men’s desire for emotionless, no-ties sex. Suggest otherwise and you’re out to spoil everyone’s fun.

So, is Sex Education open and honest? Yes, if you define honesty as Big Brother-style confessions extracted from people who show no desire to reflect.

But ambitious? What would have been truly ambitious would have been to look at the unspoken assumptions that framed the debate. Why do we assume that liberation is emotion-free sex? Why does it matter when we lose our virginity? Why do we frame sex in the language of competition? And how, most importantly, can we hope that teenagers ever see sex as something other than a nudge-nudge, wink-wink affair if we adults can’t do the same?

The Sex Education Show is on Channel 4 on Tuesdays at 8pm