You're sure of that, are you? Then maybe you ought to talk to His father, because in numerous places, He DOES tell me what's sin and what's not, and not on a case-by-case basis, but in general. That's okay. It's His world. He gets to make the rules.
And as to that "old book" with the dead authors, its laws and guidelines have defined our civilization for oh 4,000 years or so. I wouldn't be quite so quick to dismiss it. ON the other hand, the "acceptance" of homosexuality is a relatively new phenomenon, introduced at roughly the same time our culture began to go into the toilet.
In summary:
Bible = hallmark of civilization
Homosexuality = last gasp of a dying culture.
Study harder or you have no chance of passing the quiz.
"the "acceptance" of homosexuality is a relatively new phenomenon"
So is:
1) human flight
2) antibiotics
3) interracial marriage
4) freedom from slavery
5) the fight against racism
6) capitalism (by your 4000 year scale)
7) spongebob
There's more to the bible than homosexuality being a sin, and that's what's really defined our civilization. Homosexuality affects a very small percentage of our population, and many of its members are that way for a variety of reasons.
Regarding "last gasp of a dying culture": I'd say that allowing abortions would be on that list. Another thing would be any kind of tyrany, or corruption in the government. Homosexual marriage is the last gasp of a dying custom, and I'll grant that there are serious issues there to contend with. It might be better for gay activists if they stuck to "civil unions".