I deliberately say "we" and "I" throughout: talking about cruising, saunas, too much time spent on the web on gaydar - I own up to the lot, just like my gay friends do. This is not some sanctimonious moraliser looking into the goldfish bowl; it's a gay man in his 40s looking at the big open world and wondering when we are going to grab the chance to be grown-up in a society that now regards us, legislatively at least, as equals. We have demanded a place at the table, to use Bill Clinton's phrase, but now that it is laid, some of us insist on still behaving with the silly rebelliousness of extended adolescence.

When I was a student in the 1970s, what we were fighting for was visibility. That was what we needed first, just to be seen. The difference between being black and being gay has always been that if you're black you don't have to tell your mother. But the fight just to be seen and heard ended up with us defending all of our behaviour. Because the lid had been on the pressure cooker for so long, and we were defined by sex, then in order to be truly, madly, deeply gay, we had to celebrate everything homosexual. We made no judgments about our behaviour, our morality or the morals of the culture in which we swam and into which we introduced successive generations of gay men.

Some, for instance, claimed the "right" to cruise for sex. How ridiculous. We may well enjoy it, but it's not a right. The rights and wrongs are about not being arrested for it, not being killed for it. But in public spaces the issue is not whether it's gay or straight cruising, it's about whether you offend other people. Anyone, hetero or homo, runs the risk of upsetting others if they shag in public. Now we're grown-ups we have a responsibility to make those kind of judgments. But we don't. It's still almost impossible, for instance, to wonder out loud whether it really is acceptable to walk down the main street of Brighton dressed only in a thong, just because it's gay "pride". It's fun, it's a lark, but is it antisocial? Well, we still don't stop to ask. Just shut up! It's gay, honey.

We've all spent so long being told we're bent and queer and immoral and, most recently by Iqbal Sacranie, that we are "not acceptable" and "spread disease", that we have ended up making an equivalence of every kind of sexual activity, just because it's gay. So in gay magazines, while the front section is full of holiday features and interviews with gay celebrities or cute-boy eye candy off the telly, the back is full of rent-boy ads: one I read today contains no less than seven pages of them. Very pretty some of them are too. But we've normalised prostitution. It's practically an acceptable career path for any guy with a 29-inch waist and no visible acne.

And when it comes to sex, whether it's paying for it, or being beaten, or weed on, or doing it in groups, or doing it in saunas, we make no judgments about the effects on our health, emotional or mental, or the effects on our ability to make moral judgments in the world. If you question the depths and extremes of some kinds of sexual behaviour, you run the risk of being told, as I was by the owner of the sauna I interviewed in the programme, that you're not really gay: "a straight man in a gay man's body", were his exact words.

Judgments are made in the gay man's world, of course. But they are almost entirely based on looks. Gay men primp and preen, moisturise and exfoliate. Our bathrooms look as if someone has dropped a bomb in a sample shop. Some of us have six packs implanted into our stomachs, and the meat rack hangs us out to dry if we don't have perfect bodies in a clubbing world. We still even have beauty contests. And if we had the gay lawyer of the year contest you can bet it would have a swimwear section. Briefs, I guess you'd call it.

The world has changed for gay men. I have to add the ritual disclaimer that of course there's still homophobia, but the fact is that in law we have all-but total equality. Yet we continue to behave as if we are a disconnected minority, shut out from the world of responsibility. Gay men have a lot of catching up to do. Hooked on drugs and sex and looks, we call it gay culture. The figures are staggering: 20% of gay men in London use the incredibly damaging crystal meth. Studies show that men who do are twice as likely to become HIV positive. Since 1999, the figures for HIV infections have continued to rise in the UK. Syphilis infection rates among gay men have increased by 616% in the past five years.

There will be those of you reading this whose embarrassment at me washing our dirty linen in public will be rising fast. What will Sir Iqbal and the other homophobes do with these confessions? Well, he can go right back into the shameful dungeon of discrimination from whence he came. Because gay men have fought for equality and now we have a new world at our fingertips. Some of us are ready to embrace it: civil partnerships, our ability to adopt children, our real visibility in our own communities where we contribute in so many ways, from leading the fight against Aids, to campaigns that improve public safety for everyone - this is how we now live as citizens. But to embrace it we have to grow out of our teenage years of sex and drugs and mocking the old, and embrace a future of fidelity and responsibility. We're not just following the yellow brick road any longer. We're in the real world now.

·The Trouble With Gay Men will be shown on Monday at 9pm on BBC3. Maureen Lipman's column will now appear on Mondays.

This week Simon re-read Philip Larkin's Church Going, on the anniversary of a mate's funeral, where he first read it: "It reminded me of how little I believe in God; how much I'd like to but just rationally can't." Simon watched Green Wing: "Stephen Mangan gave mouth-to-mouth to a swan that he'd run over on a ski-jet. The bird died, and I nearly did, from laughing."