The shop I was trying boots on told me that womens calf muscles are in a different place then mens and the boots are built accordingly. Now, I don't know if that is true or not, but hey that's what the dude at the shop said.
Oh I have 32 womens boots and burton lexa bindings. The boots don't fit so well in the bindings, heelcup is kinda narrow for the boot. I gotta jam em in there.. So you might want to try before you buy.
That is true. Our calf muscles are lower than men's. I'd think it wouldn't matter as much for a guy (higher calf muscle placement) using a women's boot (lower design) than it does for a woman using a men's boot. I had a lot of calf bite in my old men's boots.
Great point about trying the bindings with the boot!