Why are there so few scifi movies made by women?

Most of the movies who is made today is made by men but why ?
is it because women are brought up a different way  as a child
though some climb trees  etc also books where some are unknown in some countries  as you dont hear so much about them ? here is a list of the women who write/wrote sci-fi  books and  would the movie be different  it was a woman who wrote it?

http://www.huffingtonpost.com/entry/women-who-dominate-the-universe-of-sci-fi_55ccfd02e4b0898c4886f69a