"I often wonder if woman leave engineering because they may have more financial freedom to do so. I am sure a higher percentage of female engineers are married with working spouses than the other way around (i.e. male engineers with working spouses) and so it is not such a drain on a household income for one of the couple to change careers when there are two people earning in the household."
My admittedly anecdotal experience, having married an engineer and getting to know quite a few more through her, has me agreeing with that, Turbokiwi.
"Also many men I work with feel the responsability (real or imaginary) of being the main breadwinner and much provide for their family and hence would put up with much more crap than some of us females would."
Mmmm...maybe so. I know a few (ok several, but not a majority) of male engineers that are complete bounders, and have committed serial monogamy. But, in general, I think people who study engineering, both sexes, are more practically-minded than other people. The old saw about the engineer who put the little black book into a spreadsheet and did a cost-benefit analysis to choose his(her?) best mate is probably closer to the truth than we engineers would like to admit. Maybe we are willing not to put up with more crap, but to work a little more when dating to find less crap-filled spouses?