I doubt the activity is really increasing.
Instead, modern acceptance is simply making previously closeted gays, come out about it.
Of course, among the young, it's kind of an "in" thing, until they try it and realize it isn't really for them, then feel sick about it after...and wonder why.
Hey, whatever floats your boat, I say...but if you're doing it to be "cool", that's just stupid.
My brother is gay. I'm straight as an arrow.
My wife is bi-sexual (which can be interesting at times, as I'm all for her exploring that aspect).... Hey, I'm an older guy, but I got game sometimes...(or more accurately, my wife does, hehe).... We've had a gal playmate or two half our age before. Rare, but fun.
My daughter "thinks" she is bi, but since she's never really done much one way or the other (she's pretty honest about things), eh....(she's hot to trot it seems, but due to her past (before coming to live with us), she's got a lot of hang-ups)
My son...he's just confused. He's really straight, but tries to be "cool" and think he's bi, when he really isn't. He's damn near asexual, as he doesn't have the normal drive a young guy in his 20's should have. Bunch of whackos. Oh well.