Subjective. Simply because it it debase to you does not make it universally debase.
Individuals within our species do not differ enough to claim that this is subjective. You can say "that's false", but it certainly spreads over everyone in our species. By "debase" I mean "degrading the object in question". So, pleasure sex is degrading sex to a purely hedonistic act, and that is false in rational beings. Rational beings make sex much more complicated.
Also, if it really is subjective, you have no base from which to argue with me. Subjectivity removes any and all common ground. Pleasures and pains are subjective, but logic is objective and integrated into rational creatures. The a rational creature not only has a bunch of chemicals firing in intercourse, but there is an understanding of the act, a whole dance we perform prior and after. It's called romance. Purely hedonistic sex is possible, but it leaves both men and women with a kind of wanting because there was no romance.
I like that. A 2 person family is fine, but then you claim the family is a mother and father. Without the children there is no mother or father. Period. Family is not simply about parents and kids. I have a family that is outside my blood family. I have my married family that consists of a husband and two wives. Nor does sex make a family or bring unity. An individual can be non functional in the crouch region, or be lacking equipment, and still find unity and family. You are trying to tie together things as absolutes, that in reality, although common together, exist quite well independently.
Yes, a guy that has no genitalia can find family and unity. But that's off topic. We're talking about a homosexual union of a specific romantic type; gay marriage. This guy wouldn't be doing any homosexual activity. He won't be doing sexual activity at all. And members of a family don't have to have sex (that's usually incest, and that's weird). But that's not what we're talking about. We're talking about "what is sex", where I claim sex is for a kind of unity, and "homosexual union", which I claim is impossible due to the nature of our species.
Look, here's it to you blunt: Homosexual couples don't work. I've lived in the Montrose area of Houston for 5 years or so. I have lots of 70 year old gay friends. They echo me on this. Guys get together, within 4 months someone cheats, and the split up. They never move in together because they expect the break up to happen very fast. And they say it's even worse with lesbian relationships. The girls get together, immediately move in together, and within 4 months hate each other, but now they're both stuck on the lease agreement. Gay couples that actually stay together are nearly as rare as unicorns. Why? Because there is no real unity. Our minds aren't built for that. A wire is crossed somewhere, and that's where some people look for romance. The unity is never found. Rarely you get a couple that stays together, and that's the extent of the bonding between the couples. And those are the guys that aren't having sex that often. They're more like brothers than husbands.
To reiterate, homosexuality is an evolutionary defect. Sex is still about unity, but the defect makes the individual attracted to the wrong gender to achieve such a unity. Embracing the defect is irrational. This does not mean homosexuals are less than anyone else.