It's bad because it's against God's law. In the garden of Eden, it was man & woman united in holy matrimony-not man & man, woman & woman! Another way to look at it is that the Devil hates the purity of marriage, so he tries to twist it with his own version-homosexuality. It seems harmless, but it's not, and just the fact that people debate over it SO much proves that there IS something wrong with it.