As I mentioned in my purchasing tips, I don't let the gender of the harness guide my purchase and I have bought a harness advertised as women's more than a few times because it fit me better. Outside of color scheme, it just comes down to waist and thigh size. Some harnesses have different thigh and waist dimensions between the two gendered models. Generally, a women's harness will have larger thigh dimensions with similar or smaller waist dimensions than the men's harness. That's why I recommend that folks look at both men's and women's harnesses when they find a model they like and just go with whichever one fits your body best regardless of how it's advertised.