So I quickly looked up the employee demographics for Google, Facebook and Apple (but particularly for the percentage balance of males and females, as that appears to be the hottest topic), and from their official sources the numbers are, respectively: 30% [1], 32% [2] and 30% [3].

The number of CS graduates who are women differs in how it's gauged, but it's roughly 18% [4].

Though obviously there are non-technical positions, even accounting only for tech jobs the numbers are still 17%, 15% and 20%, respectively. They all fit around the same range.

There's certainly room for improvement, but I'm not sure why the onus should be on tech companies. They seem to be doing well enough with the available resource pool. Having profit-motivated entities be the initiators of social change seems like a clunky band-aid solution to me that won't be of any particular efficacy.

[1] http://google.com/diversity/at-google.html

[2] http://newsroom.fb.com/news/2014/06/building-a-more-diverse-...

[3] https://www.apple.com/diversity/

[4] http://www.ncwit.org/sites/default/files/resources/btn_02282...