>So I don't know specifically why it is that parents, and others, discourage girls from business and technical areas in particular.
Not only technical areas, but also particular technical areas. What makes experimental physics less technical than theoretical, and chemistry less technical than physics?
Also, if you look at the percentage of women in technical fields, it does look like cultural barriers dropped. I.e., over the same timeframe that cultural barriers dropped in medicine, they dropped similarly in physics/engineering, causing women to increase from about 1970-1990. After 1990, the % women was roughly flat in all fields: in medicine at 50%, in physics at 20%.
Basically, womens liberation had the same qualtitative effect on physics that it had on medicine; only the magnitudes differ.
This strongly suggests that some other factor is keeping women out of technical fields. It could be cultural, but it's a completely different type of cultural barrier than the one that kept women out of medicine and physics up until the 1990's. It could also be biological, I don't see much evidence for or against that.
>One thing I can tell you is that women working in a field does not imply the problem is solved. First, they might be less skillful, on average. But second, they might have had to put in more effort to achieve the same level of skill, and that could be very hard to detect.
Lots of difficult to measure things are possible. I'll wait for evidence of them.
(*) By the way, I'm using physics/EE as a proxy for all technical fields, since I've been forced to sit through lots of meetings on that topic. Speaking openly in those meetings was frowned upon...