"Will and Grace" doesn't tell children to become homosexual, either. Would you get your kids the box set for Christmas because it's admittedly laugh-out-loud funny at times?
Since I don't have kids, I'll think about that in context with my younger brothers. No. First off, it's television and I wouldn't promote the watching of television in most cases. Second, homosexuality is something they could concievably try. If they try the spells in Harry Potter, nothing happens.
In either case, the teaching they've recieved tells them that either is wrong. But homosexuality is a real cultural and moral sin that I wouldn't want them to get used to, and magic is not. I don't consider the silly little rites of sad chicks who can't get dates to be magic. Magic lives only inside the pages of books and most people understand that.
And a good thing too considering the number of times they've tried to use Potter-curses on me.