I just did some Trek research and learned something--the women's madone is considered a H3 frame (relaxed geometry, more upright for recreational riders) with a different handlebar (no longer called WSD, because it can also be used by men that need shallower drops and shorter reach to shifters/brakes). If you compare the frame geometry on their website, they are EXACTLY the same However, finding a small men's frame in H3, may be harder than finding a small women's frame. A good fitter can switch everything over for you.
This came up because the WSD madone 5.2 is grey/white/pink and the men's is black/red/white.
"Well-behaved women seldom make history." --Laurel Thatcher Ulrich
'09 Trek WSD 2.1 with a Brooks B-68 saddle
'11 Trek WSD Madone 5.2 with Brooks B-17