[Sacho]

> then the only explanation is that the relative innate qualifications of people as a function of their gender changed between those two points in time.

Sure, for example, boys being encouraged to become computer programmers. There's an article on NPR that discusses this[0]. Also, when you say "the process", I'm not sure you're adequately describing the evolution of programming and its related skillset demands. A strong increase in competition would naturally lower the ratio of women to men:

- time invested in programming correlates strongly with skill

- historically men have been able to put more time into careers than women(who often need a better work-life balance to manage a household).

- the historic SMAM[1](mean age at marriage) gives men an extra ~2-2.5 years over women even if you assume equal parenting responsibility, before men must also make parenting concessions.

[0] - http://www.npr.org/sections/money/2014/10/21/357629765/when-...

[1] - http://www.un.org/esa/population/publications/worldmarriage/...