Well, since I'm not a parent, I can't really speak from that perspective.
But I'm sure some of it depends upon the child's age. Kids display their likes and dislikes early in life. I was only 8 when I thought Kelly was the most attractive of Charlie's Angels. Of course, the attraction wasn't sexual at the time (and sexuality is only a small part of it anyway). I was 10 when Grease hit the big screen and I first saw Olivia Newton-John. Xanadu was in 1980 (I was 12) and that one really got the fireworks going.
But being a young fan of a gorgeous blonde pop icon isn't really a good clue. Otherwise, parents of Britney-wannabe's everywhere would be burning her CD's. Then again, maybe Britney isn't a good example to use.
Dating habits might offer something, but there are plenty of people out there who "play it safe" and try to act straight for the sake of friends and family until they're ready to come out. However, some of the people I now know are gay actually dated gays of the opposite sex -- if that makes sense. They were protecting each other.
Who a child's friends are could be a clue. But not in my case. I have some gay friends. But I have and probably always will prefer to hang out with straight or at least straight-acting people. I'm actually sort of homophobic in that sense. I don't like the militant, left-wing, rainbow-flag-waving types. I get flack about it sometimes, but I don't care. I've been told that I'm "conforming to the straight agenda" and hiding who I really am. I don't see it that way. If anything, I'm being true to who I am -- and that's an ordinary-looking, white-bread, right-wing Republican American who likes Florida football, ER, and watching hurricanes.
Ah, there's another thing - sports. Who am I kidding? That's not a clue. I was on a swim team. But I didn't play basketball or softball or anything like that. And many girls who do are NOT gay. Guys who prefer Broadway plays to sports are not necessarily gay either.
Even when it comes to the big clue - sex - it's hard to know for sure. I've always been firm in my belief that waiting for true love is a good thing. And so I waited...until I was 27. Of course, I dated and had romantic relationships before that. Hopefully, no one's children will be doing anything (straight or gay) until they know for certain that they are ready.
So, basically, I guess what I'm saying it that there
could be clues. But you don't necessarily want to jump to any conclusions too early. And you certainly can't go by any standard stereortypes to decide if your child, grandchild, or whoever is gay.
Gosh, I don't know if I helped or confused the situation.