For those who don't like having to deal with real world numbers here is an anecdote that shows just how crazy hiring can be.
My wife was new to a company but was clearly very good at her job and had previous management experience. Within a few months, her boss started grooming her for a manager position that they needed to fill. He personally encouraged her to apply but she didn't get the job.
Her boss told her that because the majority of the managers were women, it would look bad if he promoted another women. He ended up promoting a man who recently needed remedial training and promised that she would be next in line.