Despite what bible-bashers will tell you, homosexuality can't possibly offend God. Here's what I'm thinking.
Simplistically, God wants us all to be happy. He also wants us to procreate - to go forth and multiply, as the saying goes. Thanks to the invention of sex, the two generally go hand in hand - except, of course, in the case of homosexual relationships. Fundamentalist Christians often use this as an argument that gay sex is displeasing to God because it goes contrary to his wishes and the Bible, somehow cheating the system. Some people also claim that God created AIDS to kill homosexuals.
I disagree on both accounts, and here's why.
When I was a kid, they used to say there were a little over five billion people on the planet. Now it's more like six billion. Clearly a lot of going forth and multiplying is happening. Unfortunately for mankind, the planet can only support so many people before things begin to get tricky - like any habitat which has reached saturation, not enough resources are available for everyone to live comfortably. I don't expect God to be pleased when the planet hits twenty billion and global war breaks out over natural resources.
I don't think it's a good argument that the Bible forbids homosexuality, either. While the book of Leviticus forbids it (LEV 18:22), the same book also forbids trimming one's beard, forbids touching an insect and demands stoning to death anyone who cheats on their spouse. While the basics of caring, respect and law have changed little since the Old Testament was written over two thousand years ago, it's impossible to argue that modern society hasn't updated things when it made sense to. Just as society has evolved to remove the death penalty for adultery (stoning to death today would be considered against God's will), so too it has evolved to accept gay relationships, and in the event that such relationships benefit mankind as a whole should agree that God endorses them, just as He wishes the best for mankind.
I remember seeing a pictures of some sign-carrying hypocrites someplace on the web. "God hates fags", says one sign, "AIDS is good because it kills fags" says another. No, mister redneck, you hate "fags". God loves them, just as he loves all people, while you're busying yourself by showing contempt toward your fellow man. The logic of the second argument is clearly flawed. If the disease were designed to only affect gay men, it would have a genetic limitation to only affect males. Instead, it favours those who don't wear condoms during sex - coincidentally, another invention which allows people to maintain a sexual relationship as God intended us to, but without contributing to a dangerous population explosion.
God, or nature, needs humane ways of keeping the population from reaching levels that the planet cannot support. He prefers to allow mankind to retain their way of life - living, enjoying themselves, and to put it bluntly, having sex with each other - without us producing too many offspring for the planet to support. With the phenomena of homosexuality, it can happen that while some (heterosexual) couples are busy seeding the next generation of mankind, others can maintain sexual relationships with each other without adding to a population problem.
I'm not trying to claim (as some noders have mistakenly suggested) that homosexuality is God's way of keeping us in check - that would be equating it with unwanted phenomena like viruses and natural disasters, which is totally at odds with my position that homosexuality is a legitimate way of life. What I mean is that compared to all the ways God could choose to keep our population within the limits that our habitat can sustain, homosexuality causes the least strife for individual people; it allows people to remain in sexual relationships (after all, that's how God built us) without all of mankind contributing to a disastrous population explosion. (Sounds like a fine idea to me.)
My most controversial node yet.