We bring up nursing: well, doctors used to be 100% men. Maybe doctors or biologists used to say, "Women are not interested in medicine or biology." Would any person say that now? Poets probably used to say, "Women aren't interested in writing at all." When women became poets, writers probably used to say, "Women aren't interested in serious literature." Artists probably used to say, "Women aren't interested in art- they prefer to pose as our nude models." Would anyone claim women aren't interested in these fields now? I've never taken a woman's studies class or anything but I imagine many of these arguments have occurred in the past regarding industries that used to be male dominated but aren't anymore.
I think we are generally wrong when we try to presume what a group of people would be interested in. Like who knew Japanese people would get so good at baseball? Whoever said, "Japanese people aren't interested in baseball in the first place bc they like samurai swords, not projectiles," would've been totally wrong, as wrong as whoever said, "Women aren't interested in being doctors. They get hysterical and like to sit quietly in drawing rooms," or as wrong as people who say, "Women don't like math or science or computers. They prefer art and writing and medicine and biology." Maybe one day people will be saying, "Women don't like intergalactic war travel, they prefer math and science and computers and tesseracts."
I don't feel any desire to downvote you. Here's my take as a woman who studied math at MIT and was always one of few if not the only woman in her classes/ nerd camps/ jobs throughout my entire life:
If you're the type of person who always knew what you were passionate about, you should realize this focus and passion is not common. There are some people who can explode out of some small town where everyone's main interest is football and still become a tech mogul. Most people are not like this- people do what their peers do and what they perceive as normal for whatever group they identify with. I think this might actually be especially true for children. Very few children see a scientist doing science or see something cool like a machine and then say, "Mom and Dad, I want to learn to do/make this thing," or then go online and research it. Most of the time, someone is showing the kid what they think this kid should learn or the kid is looking at stuff other people are giving to them, including their peers. Based on this, many girls who aren't deliberately introduced to tech/science as a possible interest don't realize they are interested in tech.
Most kids are friends with kids of the same gender. In middle school, when I went into a classroom to learn QBASIC as the only girl, it was less fun in every way except 1 than being in a classroom filled with girls who were my friends. I didn't make any friends in any of my middle/high school programming classes and generally kept quiet because boys made me shy, and vice versa- I also made them shy when I spoke to them. They weren't doing it on purpose- I think it's just human nature for us all to behave the way we did.
If I were less interested in programming and more motivated to have a fun classroom experience or to fit in (being a girl with my interests made me weird, which bothered me slightly but I was also interested in art so that kind of evened it out. I can imagine it bothering other people much more than it bothered me, sufficient to make them avoid this feeling of strangeness by avoiding atypical (for their peer group) activities), I easily could've not gone to those CS classes or to any of my nerd camps. When I went to a Theoretical CS nerd camp called Andrew's Leap at CMU, out of the other 30 kids, only 3 others were girls. We 4 girls were all Chinese and we became great friends. We also befriended the boys but it wasn't as easy because both boys and girls interested in Theoretical CS don't tend to have PhD's in male-female interaction or even human-human interaction.
Most kids do whatever their friends do. Most people do whatever they perceive people of their type to do. I think having a woman scientist in a popular movie does a lot more for planting that possibility in the popular imagination than many types of affirmative action programs. If anyone is saying, "Black people don't like hockey bc they prefer basketball," I think it just takes a great movie about a famous black hockey player to get more black kids to start saying, "I want to play hockey."
If I have a thesis, it's this:
1) Most people do whatever they perceive the group they self-identify with as doing. If you're a person who self identifies as an intelligent male, maybe you're more likely to think, "I should become a businessman," than, "I should become a nurse." In contrast, a person who self identifies as an intelligent female might be more likely to think, "I should become a doctor," instead of "I should become a programmer." If you're a person who self identifies as an athletic, white male, you might be more likely to think, "I should play basketball," than "I should play pingpong." People don't tend to want to be "weird" because of complex cognitive stuff to do with identity.
2) Most kids do whatever their friends do, and most kids are friends with people their own gender, and most people prefer being with their friends than not. So if you're a girl walking into a classroom full of nerdy, Starcraft-playing boys or a man walking into a yoga studio full of giggling females, you might think, "I should find another room where I fit in better," instead of discovering whether you have an interest in this strange field. Hence the chicken and egg thing. It's less fun for kids to be "weird" because being weird is lonely.