> Throw a bunch of teenagers or young adults in support groups together with the subtext that they all have the same sexual orientation with no chance of being shamed for making advances for what's effectively the first time in most of their lives, and it doesn't take a fortune teller to figure out what's probably going to be happening in greater rates for those kids.

Honestly, I think the bigger reason is that there's no chance of pregnancy in gay relationships, so one big barrier is just gone.