You are jumping all over the place, going from what God commanded Onan to do, which was to have a child with his dead brothers wife, which he decided he was not going to do. Then you talk about sodom and gomorrah??
Again the most important part of Onan, was that he disobeyed God and in his evil doing so, was killed. It is as if God called me to build a boat with these trees, and I build a house instead. Where in the bible it calls Rape and harassment alright as long as it is heterosexual?
Read your bible and it will show about sodom and gomorrah, Genesis 18: 20 And the Lord said, “The outcry of Sodom and Gomorrah is indeed great, and their sin is exceedingly grave. 21 I will go down now, and see if they have done entirely according to its outcry, which has come to Me; and if not, I will know.” This is way more then just homosexuality if everyone in the city was increasingly wicked.
And in Genesis 19 what lot did with offering his daughters to that crowd of men, young and old, was WRONG, no where does it say it was "right in God's eyes."
What are you trying to do here with that post calling me a "liberal" anyway?
Also regarding sex, it was created for more then just reproduction purposes, between a man and a woman, in marriage to be bound together, as "one flesh" to share life in the most intimate way. Children are blessings from that union, which is physically represented in the matching of each partners biological information. If you want I will give you biblical passages showing that sex is not just for making babies.