Too many politicians fear being outed. For Conservative MP Alan Duncan, outing himself was "the best thing I ever did".
From the Independent:
On 29 July 2002, I gave an interview in The Times stating un- equivocally that I was gay. It was the best thing I've ever done.
When I came out, I'd been an MP for 10 years. I'd always known that, one day, honesty was going to be the best policy. But I didn't want to make an announcement about my sexuality when I was a just a junior MP, because all I would have been remembered for was being "the Tory gay".
I wanted to make the announcement when I had established myself more, and when I could make my announcement more relevant to the direction I thought the party needed to take. As it happened, it worked perfectly. I decided to do it, and when to do it, although of course I did tell the party what I was going to do so they weren't caught by surprise.
I think it smashed a massive taboo, permanently. I was the first Conservative MP ever to come out of my own volition, and no one can take that away from me. My professional life has improved as a result. What used to bug me was that, after the announcement, people would say: "Oh, we always knew." I used to say: "How the hell did you always know? The cheek!"(Biographical notes at Wikipedia)