young Bobby Drake (AKA Iceman of the All New X-Men) came out as a gay teen. This was significant, given that he was one of the original X-Men and that he is a time-traveling mutant from the earliest days of the X-Men who's currently stuck in the present. Except that an adult Bobby Drake (AKA Iceman of the X-Men) is not gay.
So there was an unanswered question of how the young Iceman can be gay when the older Iceman isn't.
Turns out that he is indeed gay -- but deeply closeted. Until an intervention by young Iceman and Jean Grey enabled older Iceman to admit that he is attracted to other guys, but has been afraid to come out.
It all went down in UNCANNY X-MEN #600, which came out yesterday:
There has been speculation by some fans for a long, long time that Iceman is gay. He occasionally dated women, but rarely for long and rarely was it serious. Otherwise, he's been pretty much a loner for most of his life. On top of that, his father is a huge bigot. An anti-mutant bigot, but I'm sure he hates gay people also. I can see why it's been so difficult for him to come out before now.
It will be interesting to see how things evolve with two gay Icemen running around the Marvel Universe!