I don’t see the point in doing men’s vs women’s clothing sizes. Surely there’s a big enough variance in size and shape between individuals that it would be more useful to size based off of measurements of body shape?
Take shoes for example. Why is a uk men’s size 10 so wildly different from a UK women’s size 10?
All it seems to achieve is making shopping for clothes difficult for anyone that doesn’t fit into the expected body shape for their gender and make it hard to find well fitting clothes outside of specialist shops.
In many parts of the world, shoe sizes are unified (cm or mm). They still use the labels for men and women for style but, so far as I know, they’re otherwise the same (unless the widths differ, but those are also standardized in many places so you might get like a 25.5e for 25.5cm width e)