Amazon has a great bit of Gender going on if you're trying to find boots
You might think you pick Men's or Women's and a size, but no!
The sizes themselves are gendered, you have to pick size Mens-10 or size Womens-12, which is separate from the gender option

width is gendered too.
You can't get a boot that's for Women in Womens-12 in XX-wide, you have to get:
Gender: Women
Size: Womens-12
Width: Womens-XX-wide

Feet are clearly the most gendered part of the body

@foone My family have worked in the shoe businesses for 3 generations so let me share a fun but probably irrelevant fact:

Foot width is tied to your weight (lose weight it gets narrower a bit cause less pressure pushing on it), and US shoe widths are based around the *average weight* for a given shoe size and gender