Interestingly, I've heard about many people who went from "straight", married with children to leaving their families because they've found out they're gay. I even knew one whose first sexual experiences were with women, and he decided he was gay later. In his "straight phase" he could have had fathered children if he weren't careful. Curiously, I've never heard about opposite cases (spontaneous [1] gay -> straight transition). Make of it what you want.

[1] Spontaneous = ignoring attempts to "cure" gay orientation.