Wrong. Yes, there is a pipeline problem; however, women also leave STEM fields at more than twice the rate men do.[0] And when we do, the reasons we cite include the fact that it's a boys' club, as well as outright harassment.
[0]: (This is an overview, but also cites some actual peer-reviewed studies) http://www.forbes.com/2010/06/08/science-engineering-gender-...