It's not limited to womens jeans or pants. Men's jeans I've found just with Levis, a 32 waist made in Egypt may not be the same as a 32 waist made in India and neither one will be the same as one's made in the Dominican Republic.
Right now I can where anything from a 32 to 36 depending on cut and brand.
My wife and I for most of our relationship have been a similar size. We had the same brand corduroy, I started wearing those when I couldn't wear jeans to work, and a few times I grabbed hers instead of mine and they fit perfect.
When I restarted "dressing" (I've stopped referring to it as cross dressing) again I would wear her Capris around the house. Even though she's not bif or fat by any measurable standard the way she's shaped she's a size 12 short. Anything 12 to 14 fits my waist.