I don’t think discrimination in Tech is any stronger then in other industries. I suspect it is more about misconception.
There are very few women who are software developers (I know several and they are good, but I know tens times more men who are software developers).
This means that when one sees a woman in a setting of an IT company, the first assumption is that she is not a software developer, but someone from HR, QA, product management etc. It is not the person’s who makes this assumption fault – this is what our experience teaches us and it is just human to make such assumptions until we learn more.
I don’t know what can be done about it unless girls suddenly change there preference in there choice of career an decide that they want to be software developers which does not seem to be the case.