on the other hand it's a rather young field which in its early days had very few females.
Wrong.
Okay, 'early days' was not the right word. But your link actually supports my point:
In 1967, despite the optimistic tone of Cosmopolitan’s “Computer Girls” article, the programming profession was already becoming masculinized.
Now, this happened in a discriminating way,
but when the field started making ridiculous amounts of money it was male-heavy. Meaning that because of events back then today's top earners are more likely to be male. That 50% figure may very well be accurate, but it tells us little about the wage difference between males and females who are just getting into the field.
I don't want to end up next to Max though, so it might be better to drop this
@other discrimination stuff: The same effects pop up in other places. Germany, for example, has a large Turkish population, because many people came from Turkey to work in the German factories in the 60s and 70s. The stereotype goes that they are lower-class and uneducated. Originally, that may have been justified (they were piss-poor immigrants from backwards areas who held the worst positions in the factories, after all), but after 2-3 generations, there's loads of Turkish doctors, tradesmen, lawyers, you name it. Because of the stereotype, however, job applications with a Turkish-sounding name are rejected more often that applications with a German-sounding name,
even if the rest is exactly the same. That's why there's discussion about introducing pseudonymized applications, but there's still the interviews...
Now, I ask you: What's the better solution - anonymized applications or a quota for Turkish people?
My point is: People generally let their opinion of an individual be influenced by their opinion of the group the individual belongs to. That's sensible if they know nothing else about them; but if they continue to let that happen even after aquiring better information,
that's discrimination. It's kinda like Bayesian statistics...
TL;DR: We're hardwired to act as was described above, and it's not generally a bad thing; it just reflects our perception of society. We must be careful however to not let that way of thinking influence how we deal with individuals.
FAKEEDIT: That article seems... dubious, at least in parts.
Eager to identify talented individuals to train as computer programmers, employers relied on aptitude tests to make hiring decisions. With their focus on mathematical puzzle-solving, the tests may have favored men, who were more likely to take math classes in school. - See more at: http://gender.stanford.edu/news/2011/researcher-reveals-how-%E2%80%9Ccomputer-geeks%E2%80%9D-replaced-%E2%80%9Ccomputergirls%E2%80%9D#sthash.oJ2Zy1gu.dpuf