Only called womens bikes in the UK, in Europe they have more sense and both genders used step through for it's greater convenience, Step through is particularly advisable when a carrier child seat is used, it being difficult to mount a crossbar model with a child in the rear seat, they get very upset at being kicked in the head.
One advantage of a crossbar model is greater strength, but a well designed step through is plenty strong enough and can be more comfortable due to more "give" absorbing road shocks.