Anyone who chooses to avoid having children is going against their nature. Whether they do so through a homosexual relationship, contraception, abortion, or abstinance. I spoke on Homosexuallity because it was the topic in the original post, not because it is the only unnatural act.

A stagnation in race occures when the current population fails to bare enough offspring to increase the population. A regression occurs when they do not even replace themselves in the population. While by and large the human race is progressing, there are those who cause stagnation and regression.

My last coment was a side note, not intended to be part of a detailed descussion, which is why I put it in parentheses. It was a comment on the idea that homosexual activity in animals causes a high fertility (which I would like to see the proof). Because animals do not engage soley in homosexual relations they are still progressing their race. Many humans have chosen to engage only in homosexual relations and therefore have gone farther than animals in the unnatural act. This is what I meant.

Now, while I do believe these things to be biological in some way, they are more precisely described as spiritual. So, trying to prove them through physical science is not only impossible but rather silly.