Consider the possibility that one of the things that encourages women to enter the field is the lack of women in the field.

That's absurd. I am constantly recruiting for more women in my field and talking to those in school about how programming can be exciting and challenging. Many of these girls are already in computing classes, with 1 or 2 girls to 20 or more boys. It's difficult for them to know how else it could be, and it highly discouraging for them especially at an age when socializing with their peers is extremely important.

Have you talked to many women about this?

Yes, but that's not the point. The point is this comment while seeming innocent is an absurd rationalization for the behavior linked to in this post.