Just because people aren't doing something, doesn't mean they don't want to. I'm not currently doing the job I want to.
There are certain jobs I would like to do, but probably won't.
I have personal experience of women not being sure they wanted to go into Computer Science, because it's a male-dominated field. So yes, these things do happen. Even if there are biological factors that would drive women into different fields, I have personal experience that shows there are also cultural factors.
Literally no one has said this is some kind of conspiracy.
What is being said, is that women have a perception of certain fields being more for men. And having female role models in those positions makes it more likely for women to consider those positions.
Except the government isn't doing anything. The people who are doing the most to get people involved in certain fields are private companies, and universities. Companies like Google, Intel and Facebook, they're the ones that are working on hiring more. It's not the US government that is doing anything to get women into fields.