That's definitely true, and I would argue that "casual work attire" is even more ambiguous for women. One of the things I realized during my first internship is that "casual" and "casual work appropriate" aren't the same thing, even though every recruiter and manager I've spoken to has said to just wear what I'd wear casually on the weekends. There are some types of casual clothing that I wear--such as shorts, low-cut tops, crop tops, strapless anything, shorter dresses or skirts, etc--that are not work appropriate, even if this is not explicitly said or encoded in a company dress code. That being said, I would never sacrifice the luxury of wearing casual clothing to work in exchange for being able to make more straight-forward sartorial decisions.
It's not just biz-casual, all business attire is harder for women. My cousin is a lawyer in Texas, and in court the judge (yes, a judge), made a comment about her not being in a skirt. This judge was from a different era, but the incident happened within the last few years. Pretty unbelievable.
I previously worked a biz-cas place, and while everyone griped about the ambiguity, eventually you get the sense of the dos and donts and fall into line. Just takes more time.
I've noticed this as well. I'm walking around in chuck taylors jeans and a tee-shirt with a hoody in cool weather and I do it year round.
The female engineers I work with would not be what I consider casual. They wear dry clean only clothes, heals or boots. Usually clothes that are nicely fitted (As apposed to my square shirt that has arm holes sewed on. All this, +makup. (I shower, and wear deodorant, and get my hair cut weekly, but that's about it there). I could buy an entire 14 day work wardrobe for > $300.
I've wondered (perhaps worried) that is a reaction to not (or feeling) that they are not taken seriously. I can see when I walk around the halls at work that the women in my work place are putting in more effort than the guys but I don't have a cause for that.
I know that my wife likes to wear nice clothes to work. But I also know that on weekends she wears jeans and a hoody, or hoody and yoga pants. I also know that she enjoys looking at and buying clothes. I find it to be a chore, and try to do it all in about 2 hours for the whole year. I wear the same thing weather I'm doing the yard or writing code.
I don't really know why, but I can see that it's happening.
Especially as a younger female engineer, I consciously try to avoid looking younger since people consistently underestimate my technical abilities. I'm also average height for a woman but typically the shortest one on my team, so if I show up to work wearing a T-shirt, jeans, and converse I can look even more juvenile.
Yeesh... that post perfectly exemplifies how much stress women have to go through to just look "normal". I wish I could say that all you had to be was great at your assigned job, but unfortunately that's not enough (in both tech and non-tech positions).
I'll add though, that guys do deal with these rules too (see article below) but they are pretty clearly laid out. Guys' fashion changes over decades, whereas womans' changes over seasons.
Makes sense, one less thing to battle I guess. I've seen that with guys that look really young too where people assume they are the intern after they've been coming to happy hour for a year. . ..