What percentage of gay people have children?

The Kinsey Report, based on interviews with several thousand American males done in the 1940's, found that about 30% reported having had at least one homosexual experience to orgasm. It also found that approximately 2 - 3 per cent of males identified as primarily or exclusively homosexual. So far, no subsequent studies have significantly changed that statistic.

Studies done in other countries have been more or less consistent with the Kinsey figures, as well.

It's worth noting that a person can be "homosexual" -- that is, primarily or exclusively attracted to others of the same sex -- without acting on that attraction. In other Words, there can be homosexual virgins, just as there are heterosexual virgins.