Things I have Learned From Threadless:

[effex]

If I, someone who enjoys wearing tshirts fitted to curvy bodies, wear the same size as a dude's Large (L), that makes me Extra, Extra, Extra Large (XXXL). Which I can't actually buy, seeing as 'girly' sizes only go up to XXL. Better hope that works!

[just received a package containing shirts for herself (XXL) and her brother (L) in which the L was a whole fucking size bigger. thanks, Threadless!]