The best sort of mentoring and the best role models would be born out of already existing relationships:. Teachers, parents, interested professionals. I think we all agree that these relationships can have great impacts on people's lives.
The fact that NASA has created a program to mentor young girls, along with the low numbers of girls going into STEM programs, suggests that the informal system has broken down for girls and Women@NASA is attempting to make up for this breakdown. The informal system seems to work for boys so complaining about this little program for a handful of girls seems a bit petty, imo.
As for what message it sends to boys, well, it seems to me it sends the message that the industries are is designed with them in mind so they don't need these "make-up" programs. And why should we be more worried about the messages boys receive than the messages girls receive?
This reminds my of the day I went to little league football registration with my DS7, who sincerely asked, "how come there aren't any girls here?" Sigh. I wish we lived in his world.
