"Some of them include extremely young babies doing things like looking at faces, or other objects, and seeing how long they hold their interest."
I presume you mean things like "Sex differences in human neonatal social perception" from 2000? ( Simon Baron-Cohen and all that!) Found via Google BTW. Although looking at the paper itself, AND then seeing that Cordelia Fine cited and discussed it at length in 'Delusions of Gender', I'm not convinced.
Interestingly enough, even long-standing and seemingly oft-repeated effects like the new borns and replicating tongue protrusion have been challenged:
www.sciencedaily.com/releases/2016/05/160505133848.htm
(Sorry, can't find the exact reference I meant, this will have to do!).
Don't apes have culture and socialisation? Actually, DO we know if apes distinguish the sex of their infants and treat them differently? Humans certainly do!
Given the face and non-face examples used in the 2000 paper, I'm not convinced. Is the Thatcher illusion relevant here (which works across apes and humans)? Okay, stuff I can find seems to indicate that processing of faces changes a lot up to 6 months anyway, so possibly, if there is a sex-related difference at some point, this gets adjusted as face recognition algorithms are developed.
The original paper, using a 'mobile' of scrambled features versus a face, and reading that as boys supposedly prefer 'mechanical' seems a bit of a reach. To me, it seems more about FACES, and to humans, faces are distinguishable, and convey a LOT of information. Even if at the start, male and female processing is a bit different, I would be very surprised if they didn't end up at the same point, since to ALL humans, doing the correct thing with faces is still pretty crucial. And in the process, a lot of room for socialization to take effect.
I guess I'm just really sceptical about taking this (if true), to be the great blue/pink objects/people split that some want it to be. And don't get me started on the male apes prefer cars, girl apes prefer pans thing as well..................