Is one identical twin always gay?

No, one of a pair of identical twins is not always gay.

A 1991 study (Michael Bailey & Richard Pillard) in the USA found that when one identical twin was gay, there was a 52 percent chance that the other was gay too.

With fraternal twins, if one was gay, the chances of the other being gay were only 22 percent.

If being gay is strictly genetic, as many people think, then with identical twins their sexual orientation would alwaysbe the same, both gay, or both straight.