I try not to speak in generalities, because they don't apply in all cases. Off the top of my head I can think of 5 cases that defy the generalities you speak of.
Of my male gay friends, not a one of them was molested as a child, and most of them all have siblings of both sexes who are not homosexual. And my gay female friends all had 2 parent families and have both brothers and sisters who are not gay.
That's why I said 'generally'. You also might be surprised at the things you don't know about the histories of some of your friends.
"Of my male gay friends, not a one of them was molested as a child"
Or rather, not one of them admits it to *you.*
Or perhaps they are parsing words, and not counting a seduction during their teen years as "molestation."
People who suffer from disorders spend enormous amounts of energy lying to themselves and others.