I get that this is issue is very real, but the skeptic in me is wondering if there isn't an even greater related problem hidden here. If a certain group of people isn't fairly represented in silicon valley, then there are two explanations in my mind that could be contributing to this (not exclusively to each other). There could be a great deal of discrimination in this sector, and realistically there probably is. Alternatively, one could argue that something about our system of education and upbringing does not encourage women and non white/asian students to actively seek out jobs in that arena or to try and get seed funding for a company. Maybe I'm being ignorant here, but I feel like at this level, especially with the insatiable demand for real talent in silicon valley, this might be a bigger and more societal issue than just "Google et al discriminate against X." There is more that can and should be done to encourage diversity in the tech sector.

Regarding specifically the male-female gap, isn't the obvious explanation simply that these jobs select for extremely high IQ? (Men have higher IQ variance, so the further out on the bell curve you go in either direction - seeking geniuses OR seeking morons - you'd naturally expect to get mostly men.)