" It's not terribly abnormal."
Oh come on... human beings are a sexually reproducing species that produces offspring with the longest period of immaturity in nature. Humans don't have alternate reproductive strategies. The human society that disregards the fundamental truths of our species will be the next Darwin award winner and western societies with their emphasis on separating sexuality from reproduction are stepping up to that plate.
Right now the family is under duress in Western civilization. There are a number of destructive behaviors that can put us in the dust bin of history. Homosexuality with it's emphasis of being an alternate kind of family would redefine the family out of existence.
Overbreeding and our tendency to pave everything is far more destructive IMHO.