I agree a lot with the comments, but I'm not willing to totally discount the study. It's true that make and female brains are different (there is physical proof), however that does not mean that there is also not a societal component to this.
I encourage my daughter to learn to program, but I'm a programmer. There is a lot more pressure on me to also get my daughter to dress nice, take care of herself, and other things then I feel with my son.
I don't feel that it's appropriate to say parents DISCOURAGE women from entering tech fields, they just don't ENCOURAGE them as much.
That said, I think there are other reasons. Computer and robotic programs are generally also geared toward women. The programs are self contained and typically lack the complex social structure that most women like. I think the key is adding that component. Like the article mentioned above, girls need to see the social component of computer programming to see the benefit. I think many parents, including programmers like myself, tend to miss that aspect that would really speak to a girl. But then, so do many of the programs designed to get kids into programming as well.