I'd agree, but i also think this applies to both genders, it doesn't make sense for women to show too much skin for a professional environment and men shouldn't be wearing beach clothing to a meeting etc. However that being said, women shouldn't feel like they're not being taken seriously just for wearing a dress/skirt (appropriate length) or anything that resembles their gender. That's when it falls in the line of sexism, I have heard some stories on how female developers got "brushed off" at conferences for wearing a dress.