Look at the average - stereotype boy getting interested in electronics: Either they soaks it up from his environment where their parents / elder siblings play around with electronics or they fail to succeed at more popular topics like sports, so they choose a domain where the bullies won't go (because of the lack of status) or where they have a better chance at succeeding.
And make things even worse, people working in electronics aren't in most cases really the glamorous type, they have a bigger chance of being the misfit-type or the introverted type. In short, there are many people who spend a lot of time with their gadgets to succeed, which is time not spent with other people. This reduces the attraction of electronics (and similar solitary subjects) even further.
Now the big question: What does electronics offer to a girl? In most cases they already have easier areas to retreat to to get away or need it less.
From what I've seen, initiatives not providing at least some answer to this question don't really achieve much.
Korman