Do I detect a note of misogyny in some of these posts?
"Ladies" frames fall into three basic types:
Loop frames, good for ladies who like to wear skirts and enjoy a comfortable/flexible ride. Not really much use for touring.
Dropped cross frame: the rigidity of these is indistinguisable from a men's model, only a heavy or very aggressive rider would tell the difference.
Mixte frame: again only a heavy or aggressive rider would test its flex.
There is one big advantage to the dropped cross or mixte frame: the bike can be moved about with both feet flat on the ground without catching your gentleman's bits on the cross bar, ideal for negotiating small obstacles, kerbs etc.
Other advantages: The bikes are generally cheaper second hand. "Ladies" tend not to trash their bikes (bit of a generalisation there); the frame may suit a shorter rider better.
As far as load carrying is concerned, do manufacturers make "ladies" bikes out of some sort of Gurly metal? Are the axels, wheel rims, spokes, frame, drop outs all made of this stuff? Thought not.