Our culture offers us mostly gender-stereotyped clothing... so how is it "neutral" to make a boy wear clothing that socially marks him as a girl? Reminds me of the Johnny Cash classic, "A Boy Named Sue." So these parents are experimenting to see what happens to their son when they send him to school in girlie clothing? I hope the kid doesn't get beaten up too badly.
It's taken us several decades just to accept long hair, stacked heels and earrings for males other than pirates. Frilly blouses and swimsuits? Not yet (pace, Sir Elton John). And it's barely a century since women wearing trousers were considered whores and/or deviants.
A 20-something female relative prefers to buy casual clothes in the men's department because she thinks today's girlie fashions look vulgar and lewd--think skinny jeans and midriff-baring microtops. And as small kids just a year apart in age, my sister and I had no qualms about interchanging our toys--dolls, soldiers, "pink" and "blue" books, games, etc. But nobody forced any of us to "bend" our gender behaviors. I think our parents were smarter than these misguided cross-dressing advocates.
Not a sermon, just a thought! Peace.