Read my post again carefuilly and this will answer your question.

Anyway, look up Gay Bowel Syndrome and then tell me how it isn’t harmful, Mr. “I’m a scientist.”

Carl Marx underlined the danger of uncontoled capitalism as it has the tendecy to become extreme.
We can see this hapening right now. Since the end of the cold war there is nothing to contain capitalism.
Carl Marx predicted that capitalism will self destroy unless it is controled. But Carl Marx also correctly predicted that Communism would self destroy as it did. He also said that extreme capitalism is equivalent to comunism because all the powers end up into the end of few people in charge of few megacorporations not working under democratic principles thus stoping human progress.

Carl Marx while underlining brillantly the problem with capitalism never proposed any solution to it since he saw the same danger in both systems.

I am strait so I am neutral on this issue. But I am a scientist and I am sorry but there is no evidence of that.
If she was thinking about STD (Sexualy Transmited Disease) it is true there is a danger to be gay but there is also a danger to be straight.

The harmfull life time is promiscuity regardless of sexual orientation.
For some reasons Gay have the tendency to be more promiscus than straight. This is the only thing.

And now the shocker for women it is actually safer to be lesbienne than to be straight.

Personally I am totaly faithful with my wife and I would have remain so even if they were no STD.
Faithfulness is part of true love after all.

This beeing said I observe a cardinal rule not to tell people how to conduct their life and not to judge them unless they ask me to do so.