A few days ago, Lea Coligado, a junior at Stanford, wrote about some of the sexism she's experienced in computer science. One of the things she mentioned was how wearing dresses caused her to be treated differently. I, too, prefer dresses because I find them much more comfortable than pants; I (probably) wear pants once or twice a year outside of the gym and cleaning my apartment. I, too, have noticed that people treat women differently for deviating from the "software engineer uniform" of jeans and a t-shirt.
It seems like fashion choice shouldn't be that big of a deal within academic environments and the workplace, as long as it's appropriate.
An acquaintance mentioned that he gets treated differently when he wears nice slacks to his workplace. His experiences match up with the ways I've seen my male friends get teased by others in the industry for dressing up, and they'll hear comments like "Oh, are you going on a date tonight?" and "What kind of occasion could be cool enough to warrant putting in that much effort?" Both my friends and Lea are dressed up because they think it's important to "seem like they tried", and they both get responses for it.
It is unfortunate that our industry questions people who choose to regularly or occasionally dress up for work. But there are a couple of ways that this bias manifests particularly badly for women.
The first is that wearing a dress and "dressing up" aren't the same thing. Similarly to how there are places where jeans and a t-shirt would be highly disrespectful, there are dresses too casual for many settings as well. Many women, Lea and myself included, wear dresses for the same reasons that many men in software wear t-shirts: comfort and personal preference more generally. It's no more of an attempt to flirt than wearing a witty t-shirt; it's just another option.
On top of that, the responses I've gotten when I've worn dresses are usually directed at my character or skill level. The kindest of them call me naive or better suited for non-engineering positions: "Software engineers learn they don't need to dress that way." Men, too, are mistaken for different roles, though for dressing up as opposed to simply wearing a different article of clothing. However, women are told much more frequently than men that they are just not suited for the positions those people already know they hold: "Real coders don't focus on fashion." I've even seen men who don't dress the part get extra credit for commanding respect in spite of their atypical clothing choices!
Clothing choices have nothing to do with technical ability, and conflating the two will only help perpetuate the gender gap in an industry that already has a serious problem retaining women.