Anecdotal evidence/sample size one story: My wife has a doctorate in chemistry and 2 postdocs under her belt, but she had to leave her field purely due to sexism she encountered during her post docs. The PI (her boss) was quite abusive, outright sexist and a horrible racist. My wife wanted to move on to industry jobs but her wouldn't let her leave. So he kept giving bad references. We didn't know about this until after my wife looked into why she got rejected.