seemed like a losing proposition--I wouldn't be happy doing it and people would figure out what I was really like sooner or later, anyway. I figured that anyone who wouldn't/couldn't like me for the person I was wasn't anyone I wanted to waste my time on, anyway.
Although I never played dumb, I have practiced "selective silence", although I've only done that in certain situations as an adult. I'm a techie type but also happen to be a pretty decent singer. While I was serving ten to life in graduate school, I sang in a small audition-only ensemble. Most of the other people in the group were master's students in vocal performance, so a crop of them would wash in and out every two years. When a new batch would come in, I was careful not to volunteer that I was working on a Ph.D. in a tech discipline for the first month or so. I noticed that once people had sung with me for multiple rehearsals, I didn't get that "oh" reaction when people found out what I did. That's not entirely gender-specific, though. My husband's also got a Ph.D., and that's not a piece of information he volunteers about himself when meeting people in a non-technical setting, either.
I remember the "smart girls don't get dates/husbands" being very prevalent when I was in middle and high school. At the time, I believed it was probably true but couldn't see myself saddled to someone stupid or shallow. Now that I actually am overeducated, I can't think of any female PhDs I've known who aren't/haven't been married, including one lesbian who came out after her divorce.