Q.I am concerned about the 8-year-old next door -- the son of our friends.

He is well behaved but sometimes he acts more like a girl than a boy.

He, my daughter and my nephew are in the same third-grade class and play together after school, but when I asked my nephew if he ever plays with the boy during recess, he said no, because the boy would rather play with girls. On another day, my daughter said that he doesn't just seek out the company of girls but that he likes to pretend that he is a girl and that he often wears his mother's shoes at home.

That's when I started to pay more attention.

I noticed that when the kids are playing with action figures at my house, the boy usually fights my daughter to get the female ones. I was even more disturbed when I picked up my nephew and my daughter from his home and found that he was wearing lipstick and rouge. When I asked what was going on, they told me that he had wanted them all to be girls, but even my daughter wanted no part of this makeup game.

I am not sure if the boy is just in a phase or if this is his real nature.

Eight is awfully young to manifest these behaviors, isn't it?

A.No, it isn't. Children, even very young children, are sexual beings.

Although boys have always been expected to be boisterous and competitive and girls to be gentle and dainty, there is a wide range of natural behavior.

Some boys do pass through a feminine stage (which usually upsets their parents), and some girls are tomboys for years (which seldom upsets anyone). But if a child routinely thinks he belongs to the other gender, and if he is always attracted to his own sex, he may indeed grow up to be gay. It's much too soon to know.

Most scientists think that a person's sexuality is the work of nature, not nurture; that it is as innate as the color of his eyes and just as immutable. A homosexual can no more be attracted to a member of the opposite sex than he can be attracted to a lamppost.

So far, studies have found that some homosexuals are born with what's called "the gay gene" -- which is turned on in some people but not in others -- or that their hormonal environment in the womb was different or that they had very early influences in brain development. And these are just the early results.

Even if you were sure that the boy next door is gay, you don't have to worry about his friendship with your daughter and your nephew, or that he occasionally wears high heels and makeup. Homosexuality isn't catching.

You just have to establish the same rules of play for the three of them that you have for all children, whether they're playing at your house or theirs.

If you're lucky, these rules will last for the next 10 years.

* Don't let anyone touch your body -- and don't touch anyone else's body -- in any place that is usually covered by clothes.

* Don't play doctor.

* Don't take off your underwear.

* Don't shut the door when you're together in the same room.

All children need these rules and all children need acceptance, too, especially your young neighbor. His parents must be doing a good job of that, because he seems confident enough to be himself, but he needs others to accept him, too. If you let him know that you are his friend, you will give him extra courage, and if he finds that he is gay, he will need a lot of that. It's tough to grow up straight but it is even tougher to grow up different.

This kind of difference will be hard on his parents, too, no matter how enlightened they are. Be prepared to listen if they confide and to reassure them if they need reassurance.

You'll find good material in "Living With Our Genes" by Dean Hamer and Peter Copeland (Doubleday; $14.95), and check with Amazon.com for a copy of the out-of-print "The Sissy Boy Syndrome" by Richard Green. (Yale; $19.95). It's a bit outdated but still a classic.

Questions? Send them to advice@margueritekelly.com or to Box 15310, Washington, D.C. 20003.