Pretty much everyone in programming knows it’s a male-dominated field. However, there are still some women in programming – about 28% of computer science degrees go to women, according to the New York Times. What’s more striking is that famous women technical startup founders seem to be, not just rarer than men, but close to totally nonexistent.
28% works out to a gender ratio of about 3:1, which is pretty slanted. But if we look at the data for self-made billionaires (in the US), we find that only about 1% of them are women. That’s more like a ratio of 100:1. And none of them have technical backgrounds. It’s hard to get good data on startup founders generally, but the number of female Y Combinator founders is in the low single digits, and a lot of them also have nontechnical backgrounds.
How did that happen? There aren’t that many women in computer science, but there are some, as the data on college majors indicates. There aren’t that many women in tech startups, but there are some (Meg Whitman, Carly Fiorina, Caterina Fake… ). 1% is just really low – for comparison, about 4% of lawyers were women in 1960, and that was at a time of blatant discrimination, when Harvard, Yale and Princeton didn’t admit women at all.
Why? I don’t know. But it does seem worth noticing that there simply is no female equivalent of Bill Gates or Larry Page or Mark Zuckerberg.
The Rationalist Conspiracy 
you don’t need to become a billionaire to get laid if you are a nerdy female.
I’ve thought of this for a while, and I think it’s just as simple as multiple overlapping factors.
The world of technical people is (fairly) male-dominated.
The world of business people is (moderately) male-dominated.
The world of people with extreme career ambition, not just high but way out on the long tail — CEOs, Presidents, Fields Medalists — is highly male-dominated.
It’s harder to find a woman who meets all of the above criteria than to find a woman who meets just one.
I think the title question is too specific. Self-made women are rare and this needs explaining, but they are so rare, it is hard to make more specific claims. According to your link, there are only 4 American women who are self-made billionaires, 1 of whom was in tech. There’s no reason to think that tech is underrepresented compared to any other field. Y-Combinator numbers may suggest why rich women are rare, but the explanation shouldn’t be specific to tech.
(If we include Sara Blakely, 3/5 self-made American women billionaires are in clothing. So maybe clothing is overrepresented, but I see no reason to identify any particular field as underrepresented.)
http://www.lagriffedulion.f2s.com/math.htm
That is why?