When did 'homosexual' become a noun?

We had a rather heated debate today in my ethics and values class about homosexuality. We talked about whether it's right for them to marry, to raise kids, or just if it's ok for them to be homosexual. I have another, related issue I'd like to rant about. When did it become a noun? Imagine being a kid growing up with this debate going on, and everyone talking about homosexuality as something that some people are and some people are not. With all the hormones and such going on during puberty, it's already a pretty confusing time in life. When we talk of homosexual as something that some people just are, doesn't it reasonably follow that kids are going to feel a need to define themselves in terms of this distinction? Do you think that's wise? Is it good for a kid to look at himself (herself) and notice traits that some people ascribe to homosexuals and then follow by thinking "well, maybe I'm just gay" do you think that's good? I think it's pretty clear that the way everyone talks about homosexuality as an "is" rather than a "does" confuses the issue. Now let's look at whether or not it's valid. Someone close to me has chosen an alternative lifestyle. She grew up Christian, married a man, had kids, raised them, had some problems along the way but don't we all? Eventually, she decided she'd be happier living with another woman. It bothers me to describe her as "a lesbian," but not because it bugs me that she lives that way, but because that's simply not who she is. It's something she does, it's a choice she made, but that's not who she is. She's a caring woman, she's kind and considerate, she works hard, she keeps her home beautiful, she was a good mother. I don't think of her as "a lesbian" nor anyone else who chooses that lifestyle. It's not something you are, it's something some people do, and something that people start and stop doing at points in their life.

I can't rant about this anymore. I just can't stand it. You're all blind.