Morality is based on a societies values. Once a society has deemed a practice moral, then that practice is no longer immoral.
Homosexuality is considered immoral because the majority of our society has said that it is wrong. It might be considered a moral behavior if society can deem it appropriate. But until a majority of people living in the same society can accept homosexuality, then it will still be considered immoral.
Homosexual unions cannot pass on children, thus genes cannot be passed on, and evolotion does not continue. This is going against nature.
If a child is involved, Psychologist have agreed that children need both male and female guardians in their lives to be properly adjusted. Although in a homosexual union, one partner is more masculine and the other is more feminine, both partners share the same sex and on some level masculinity or femininity. Thus a child will not gain the proper understanding of what it is to be a man or woman.
CHICKY...
You miss my point. I'm not saying that society is right or wrong in justifing homosexuality. I'm just saying that society has already stated that homosexuality is an immoral behavior.
Look at another behavior, smoking. Smoking used to be accepted all over the place, restaurants, air plane's, etc... Now smoking is limited to only a few select places. You could argue that smoking was moral at one time because it was accepted. However, society has changed and denounced smoking, so you may argue that now, smoking is immoral.
As for family traditons, there are always a few cases where children are better off with homosexual parents. However studies have indicated that a traditional marriage is best for well adjusted children. Children need strong male and female role models, and more often then not, they look to their parents as these role models. A child with 2 dads will not have a strong female role model, or vise versa.