I've read elsewhere how in the earliest days of computers, men designed the hardware and relegated the programming to women because it was seen as clerical work, albeit advanced clerical work. Because of this, women, such as Grace Hopper, became well established in the field.
The advent of the Apple II and TRS-80 exposed kids (including myself) to computers, and with these machines, programming was the most accessible aspect. You could try to modify the hardware, but then you risked ruining the most expensive piece of equipment in the home. However, you experiment all you wanted with the BASIC prompt, and that's how I learned to program. There is something different about girls and boys such that this kind of tinkering with gadgets appeals much more to boys than girls.
I remember excitedly showing our new Apple II to my cousin who is 6 years older than me, and who had recently finished her CS degree and was working in "data processing." I expected her to have the same gee-whiz reaction I had, but she was not impressed. To her, the Apple II was a silly and expensive toy.
I think that in a way, when myself and other male "Micro Kids" entered the university and professional CS world, we changed the dynamic from a more professional to a more hacker-like culture. Not only did our numbers heavily tilt the gender distribution, but I think we also made the culture less attractive to women.
My cousin, now in her late 50s, is still in IT as a higher-level manager in a large oil and gas firm. Right now, she appears to be spending a lot of time dealing with the logistics of some major office relocations. It is probably the kind of work that many on HN would consider boring, but I am sure it is essential to the smooth operation of a large modern corporation. When I hear her talk about her work, she comes across as being more responsible and practical than her younger male peers, and I don't doubt that's the case.