See, I'm a feminist and most of my mother-peers are. No, actually they all.are, we all talk about it. Anyway, I was out with three other mums - me and my DS and DD (though DD is a baby), one mum with two DSs and two mums with one DD each. We decided to eat on the way home and took our bunch of tired preschoolers to somewhere we could sit outside, really to minimise the damage/ destruction potential which is quite high with six tired preschoolers. Right from the start it was quite chaotic but what I really noticed is that the two mums of girls were way more remonstrative, way more.authoritative in relation to what I and the mum of two boys thought quite minor infractions - e.g., I'm okay with mine messing with the salt cellar within reason but the girls' mum's didn't even allow that.
I've read the (vile) SMOG threads, hell, I've read Cordelia Fine, (and de Beauvoir, and Greer, and Irigary, and Cicoux, Butler, Young... etc). And I really thought I had a heads up on this. And that my smart, well.read, feminist friends had it covered. Bit it did.look an awful lot to me like we were right then and there expecting better behaviour from our girls than our boys.
It's insidious isn't it? I know I have to check myself nearly every fucking time from commenting on friends' daughters' appearances. It sounds OP, like your DH is checking himself in a similar way - I mean, at least he noticed. But I'm not so very sure that giving DS a doll or pointing out diggers to DD is going to solve this one.