In my dc's case they will probably get a really bad rash, for a start. And then you have be a bit thick if you can't work out why some people don't like the normalisation of makeup for very young girls, and all the attendant issues.
This. And I should add I've discouraged people who asked what my just turned 4 year old DS would like for his birthday from Batman/Spiderman/ninja turtles stuff and trucks - frankly, he has a million trucks, and there's enough stuff around in his life, not least from older kids at his childminder's, which encourages fairly violent combat play.
Not that he doesn't play these kinds of games too, but I'm not keen on him being socialised to think that because he's a boy, he's only supposed to like violent toys and to have an emotional vocabulary limited to karate-chopping people on the windpipe and grunting at a PlayStation, any more than I would want a daughter of mine to think she was supposed to look a certain way in order to qualify as a girl, and that her enhanced appearance was the most important thing about her.
Which is what is behind something that appears to genuinely baffle a lot of Mumsnetters, who have some kind of obsession with Pink and Barbies Being Allowed For Boys But Not For Girls, but seem unable to understand why some parents might legitimately have this take on things.
The rest of a young child's environment -- from older children, friends' dopey parents and comments about 'real boys' and double standards about whether tears from a four year old are ok, depending on the sex of said four year old,TV advertising, clothes ('pretty' for girls, tractors and 'Here Comes Trouble' slogans for boys etc), the gendering of toys into boys' and girls' aisles in shops - is giving them fairly limited and stereotypical messages about how they are supposed to be.
Which is why running around dressed in a frilly pink tutu with a Barbie pretending to be a fairy princess might be genuinely expanding a little boy's play horizons in terms of the way he is 'allowed' to be, whereas the exact same scenario for a little girl may well be only pressing home the usual messages of female passivity, domesticity and prettiness. It's hugely different, because the messages little boys are girls are still getting from the rest of society are hugely different. Still, in 2016.
Surely that isn't that difficult to understand?