Is women's underwear designed by men?

Hardly.

Marielle Bollier - inventor of the "minikini"

Ninette van Kamp

Marlies Dekkers

what makes you[a female] better able to understand their situation than me[a male]?"

..then the source of pressure (male domination or peer pressure) is secondary, living under the pressure is primary.

_{*Lunatic*, n.
One whose delusions are out of fashion.}

Would things be any different if women designed women's underwear?

Good questions, although I feel they're entirely beside the point.  It's not about the actual underwear (or burkas), it's about what the articles of clothing represent.  

As I said in more detail above to TBG, the clothing itself is merely a symbol (and often a tool) of the cultural problem, so when clothes are used to manipulate us, ether by politicians or industry, we take it personally for reasons we often can't, or don't want to, articulate.

Maybe we can eventually make language a complete impediment to understanding. -Hobbes