It weirds me out to find people who believe that these preferences are solely due to cultural pressure. It reeks of ideological blindness to me.
While, sure, you can raise children to be much more willing to challenge gender norms, and you can raise them to not hide or be ashamed of where their personal preferences violate cultural gender norms, every parent I've known that have strongly believed it was all cultural have ended up changing their mind after they've tried their hardest to give their kids gender neutral toys and clothes, or a mix of "boys" and "girls" stuff, and found their kids even at toddler stage gravitate to "typical" boys/girls stuff.
I think it's great they give their kids the choice and don't judge if they pick stuff that doesn't "conform", and I personally find it very annoying how e.g. clothes stores often draw hard lines between boys and girls stuff even when there's not even a half-plausible reason (no, a minecraft t-shirt for a prepubescent child is not gender specific in any way), but at the same time I also personally saw my son express a very strong preference for or against certain things related to gender identity from he was very little, and if we'd tried to push him to ignore that preference we'd be just as bad as parents who push for conformity.
I don't think this is necessarily a bad thing in and of itself, but I don't think it proves anything innate in gender either.
Another part of the problem is our language, and the way we think about it. We have a tendency to say "girls prefer this, and boys prefer that" as a short hand for "on average, girls prefer this and boys prefer that". Those two statements are not the same thing at all. Averages don't say anything about how any individual person thinks. This shortcut of language seems to be a big blind spot in people.
Even just hours after being born?