Some people hate a 'slippery slope' line of reasoning, but to me it makes sense. The slippery slope says that other lifestyles will also be legalized if the Scotus rules in favor of homosexual marriage. Scalia argued vehemently in that regard in the Scotus' last foray into homosexualism. He was ignored. Time has proven him correct.
So, you are right on the money.
Yes, and I wasn’t even necessarily keying on the legal aspect - just the logical aspect.
If sexual orientation is inborn, then ANY sexual orientation is inborn, period.