The issue is not necessarily hiring. There was a story on HN a while back saying how Facebook recruiters had stopped bothering to target women specifically beca

The issue is not necessarily hiring. There was a story on HN a while back saying how Facebook recruiters had stopped bothering to target women specifically because even though they were heavily incentivised to do so, the FB hiring committees weren't on board with the whole positive discrimination thing so it wasn't working. However, the big tech firms do seem to have a problem with firing. I've heard this several times now from other people and saw it myself when I worked at Google. Hiring is never 100% accurate and so even if hiring itself is unbiased (questionable at best), without unbiased firing the quality of that segment of the worker pool goes downwards over time. Even though the engineers often truly believe in a meritocracy, HR in particular is a strongly female dominated profession and unfortunately I do suspect a "sisters gotta stick together" mentality because I saw within the span of a single year at Google a man get canned for merely not being particularly productive, whilst a woman who openly and repeatedly lied in meetings (and lied very badly at that), and who caused her team huge heartache due to her terrible quality work, was not only not fired but in the end promoted into management. It was widely known that women who weren't very good or caused trouble were almost impossible to get rid of and were typically transferred around between teams rather than shown the door.