Marriage discrimination struck down in Arkansas.

[Silver]

Unless you believe God created all sexual orientations equal there is no reason to believe nature would just make them all equal. Nature doesn't care if one orientation adds more value to a population than another. You've simply decided they are because in this respect you wish nature to be egalitarian.

You are falsely assuming that unions are only valuable if they contribute to the continuation of the species via procreation.

Nature, after all, seems perfectly fine with both the heterosexual and homosexual orientation, for even animals display propensities for both orientations within nature.

Only theists seem to have a problem with homosexuality. Therefore, the abnormality lies with theists and not with nature.