My second motivation can be illustrated by this graph that shows the fact that most potential geek girls stay out of computer science and engineering. While the number of women have caught up and surpassed the number of men graduating from college, the increase is in "other fields".
Now some articles that I've read over the years have suggested that the reason for this is that women just aren't interested in engineering, and this may well be so. However, the gap between men and women in graduating engineering degrees is significantly more in America than in other countries.
So, I got to reading to see if there was anything I could do, as a concerned "geekdad",
Additional Notes
“Though girls take just as many advanced high school math courses today as boys, and women earn 48 percent of all mathematics bachelor's degrees, the stereotype persists that girls struggle with math, says Hyde. Not only do many parents and teachers believe this, but scholars also use it to explain the dearth of female mathematicians, engineers and physicists at the highest levels.” —Taken from No Gender Differences in Math Performance
See also the following articles:
Girls do as well as boys on math exams (see here)
Girls perform as well as boys in gender equal societies (see Bridging Gender Gap)
Young children think gender-related behavior is inborn (see here)
Culture, not biology, underpins math gender gap