I know! It was really annoying. I just wanted to get stuck into computerized maths, CAD and plotting when I was 14 but it was uncomfortable being the only girl in the lab during lunch hours. If there had been another boy or girl I respected as a friend there I might have joined in, not to be sociable but just knowing there was someone else there who wasn't geeking out on gaming.
I think the solution (for schools, anyway) would be adult-led structured activities where intelligence and hard work are rewarded: electronics/robotics/programming clubs, with long-term group projects where people with varied levels of experience can be accommodated.
I'd naively like to believe that gender can be left out of it, other than making a structured effort to recruit students irrespective of gender.
I had never had it explained to me like that - maybe girls and boys separate themselves so much as teenagers there's just a huge amount of information we don't have. If I was back at school and I knew that I would have had no problem hanging out in the computer lab, knowing that what was going on was a male-growing-up thing and outside of my participation.
I believe that we can have gender-neutral education. Sports is good at it but women and minorities fought hard in the 20th century for equal right to the field. Something to think about.