Perhaps you are not aware of this, but there are numerous studies that show bias, for example random shuffling of names on resumes and resumes with female names are rated lower than those with male names. Whether this bias is conscious or unconscious is of course hard to establish, but I think it's beyond dispute that it exists.
I am aware of them, but I am not convinced they tell the full story. For example there was the one of professors choosing PhD students (or assistants, something like that). It seems possible that they acknowledge the likelihood for women to drop out is higher than for men, so women are simply the worse investment. The bias was also shown by both male and female employers. The elephant in the room is: what if they had reasons to be biased (like having had the experience that women drop out)?
Also, it doesn't seem as if getting hired is the problem for women in tech, the problem is that there are not enough applicants.
And there also studies showing bias against men. For example the one where they made women conduct phone interviews with male voices and vice versa, and the women did slightly worse when they were given the male voices. There was another one were women were twice as likely to be hired for tech jobs than men.
I'm too lazy to look them up, but I find it interesting that only the "poor women" studies are being mentioned, and the others are quickly forgotten.
