It is very true. The proportion of women in hard science courses is small. Take any engineering school, graduate student population in math or math faculty. I'd say that, among math majors, they are 25% of undergraduates, 15% of graduate students and <10% of faculty.
The only field that, IMHO, is worse is computer science. Much to the dismay of this single mathematician.
My education (BS -- MBA -- PhD in Industrial Engineering) spanned 20 yrs., and the number of women declined in the "hard" subjects over that time. E.G. Most of the Math majors were girls/women when I was a math major; the guys were taking math for engineering, not as a major. I also worked in programming and systems, there used to be quite a few women. However, I was the only US woman in my PhD program.
My thought: girls/women are "self-selecting" themselves out of higher math and science at an earlier age. There used to be more required core courses; now there is more "choice". Why work hard learning math, after all, when you can get a "real" degree in a "soft" subject like womens' studies? ;)
Want to read something that is frightening? Creating a Dumbed-Down Populace - to Accept Global Governance
It's a long piece, but it explains clearly what we have been watching for 50 years, the HOW, the Who and the WHY behind it!
Check out the community colleges .
Both of those where I am teaching math courses
as an Adjunct , have many women teaching Math !