- It is an alarming (to some--not surprising to me) and fairly heavily researched phenomenon that women drop out of engineering fields with much higher frequency than men (link).
- More than 50% of women drop out of technical university in Germany (link).
You can read about women in engineering in one of the largest surveys on the subject. I found this on Erin Taylor's blog, where she discusses various issues with retention of women in engineering programs.
Here is a link to a paper On the outer: women in computer science courses about how being in a primarily male domain makes things difficult for women:
After more than three years researching the question "Why women drop computer science" at Victoria University of Wellington in New Zealand, I am surprised so many women succeed given the overwhelming odds against them. Women who take computer science are 'different' not simply because they are women, but because they have chosen a subject which has been primarily a male domain. Once enrolled, they find themselves 'on the outer', facing difficulties not usually experienced by white middle class men who take computer science. There is evidence that other minorities also suffer alienation in what is essentially a distinct subculture whose origins will be discussed later.
I also found an online chapter to a book Barriers to Women in Science and Engineering by seemingly reputable people, including a Columbia CS professor, discussing the difficulties women face at every stage of their career. As this supports many of the points I made earlier, I recommend that you read the chapter:
We find, instead that women face barriers to entry and achievement at all stages of the academic ladder. We have identified a series of mechanisms that mitigate against the progress of women in academic careers in science and engineering. First, such extra-academic factors as the differential socialization of men and women and marriage and family. Second, the normal working of everyday features of academic science such as advising patterns have the unintended consequence of excluding women.
Thirdly, there are sources of subtle and not-so subtle bias derived from the taken-for-granted male model of doing science that also discourage women from full participation. Needless to say, these characteristics are often intertwined and a phenomenon discussed in one category of analysis will also overlap into another. In the following sections we discuss examples of each of these three types of barriers to entry into scientific careers and offer suggestions as to how they can be eliminated or at least lowered.