What would be the harm?

[Angrboda]

It seems to me that sexual morality is largely imposed by those looking to piggyback their DNA on the acts of others.  A father, for example, quite jealously guards his daughter's sexuality, because if she breeds with some dumbass, his gene pool takes a hit, and thus his own genetic fitness has been affected by proxy.

I think this is pretty clearly seen in the differences in response to young girls' and young boys' sexuality-- a girl having sex too often too young is seen in much worse terms than a boy.  When I was young and got a girl to spend the night, my father found out and started bragging to his friends-- "So. . . guess what the boy dragged home last night?"  *wink wink nudge nudge*

This is the essence-- harm is defined not only rationally, but in terms of our ape instincts, and while we dance around it with various semantics, under the hood those will be there for tens of thousand of years, or until we genetically modify them out of the gene pool.

You say that like it's a bad thing!

What's the alternative? And if there is no alternative, is it objective on its own terms?