I don't know that skirts would necessarily confer a disadvantage, as the Scots managed some pretty fierce close encounters in kilts, though I can easily imagine that some styles would be far less suitable. And pumps can offer a weapon in and of themselves, though like any weapon, it requires practice in the maneuvers to be used for them to be effective as such, and I've seen precious little of that in practice.
There are advantages a woman can use to her advantage, however. Though some folks suggest dainty little handguns such as Smith and Wesson's former *Ladysmith* line for women users, not at all a bad choice if worn on the person, those who carry in a handbag or purse can utilize full-size, full-power service handguns if that suits them, as do two of my previous lady friends and one cop-wife neighbor.
The cop wife carries a duplicate of her hubby's .40 Glock service automatic, and her dinner-dress bag additionally has two accessory pouches on it just right for two spare magazines apiece. My lady friend who's an Air Force veteran is as happy with her 9mm Beretta M9 handgun on which she was reasonably well trained at USAF expense and which she carried on her tour through Desert Shield/Storm as I am with the .45 automatic and 9mm Browning Hi-Powers that recall my own time in the Army. And the third simply notes that her own purse is often an uncoordinated jumble, and a large handgun is easier for her to find through the clutter than a smaller one might be. For their own reasons, the approach works for them; others would prefer to carry on-body, lest a successful pursesnatcher get something other than what they might deserve.
-archy-/-
Criminals are generally stupid. If you point something like a saturday night special at one of them, they won't be as scared as if you were to take out a huge revolver. Both guns, if fired, will allow the victim to get out of a dangerous situation, but a flashing bigger gun carries a bigger message, and you will have to use it less and in turn, spend less time defending yourself in court.