[pron]

> Side note: drops like this have occurred in other fields at different times. Psychology actually ended up losing a lot of men in the 70s, while women increased. I am sure we could find a few other examples as well.

Absolutely. Many researchers compare those shifts with changing attitudes towards certain professions (say, by counting certain words when they're described in the media etc.), with women participation usually correlated negatively with prestige.

In any case, much of the distinction between masculine and feminine professions is traced back to Victorian times. Of course, similar differences have existed much longer than that and in many cultures, but the Victorians elevated the distinction between gender roles into an elaborate system of social codes (e.g. they had certain rooms in the house more appropriate for men to spend time in, and other for women).