[frogjerk]

It is against the natural law. It is against biology.

[Logic n' Reason]

It is against the natural law.
And specifically, what "natural law" might that be? Are you applying this "natural law" to just humans, or to non-humans (animals, insects) as well? And are you referring to "gay marriage" or homosexuality?

It is against biology.
What is "it"? Are you referring to "gay marriage" or homosexuality? If you are referring to pro-creation, then I would suggest there are huge numbers of parentless children strewn about just begging for a comforting home.