Homosexuals have been present in every culture. If you want to talk specifically how that looked on a particular culture, go for it. You choose.<quoted text>
That's simply false. Many cultures have had homosexuals: Greeks, Romans, native Americans, China, Japan, etc.
Procreation is neither required as part of marriage nor is marriage required to procreate. They're not even expected.
The government has an interest in seeing people in committed, stable relationships. It proves better both for the participants and their children. And these benefits apply to gay couples as well as straight couples.
You are not addressing the issue of discrimination that occurs when children are removed from consideration. Nor are stable couples a prevailing interest got the government.