The problem starts even before formal education. In the country I was raised in, young women get an education which can be summarized by "get a husband to take care of you, cook and have his children". As long as parents have this mentality, their girls get no incentive to continue with college or anything technical, because this path is unknowingly inhibited since childhood. Most developed countries rely heavily on imported workforce, so a lot of Yahoo's and Google's employees come from countries where the percentage of women graduating in tech is far less than the 18.2% of women graduating in the US.