This wasn't a sexist joke. This was a sign of a sexist culture, which is much more pervasive and damaging.
Women are just as competitive as men
Men don't have to take this crap. Well, usually.
he reason they stay out of tech has not much to do with sexism
So, what is it?
Also, your mention of sexist culture makes it sound like that's the culture in technology startups, this is not true. Sexism, where it exists, does not depend on the domain. Its pervasive.
And why is there a lack of role models?
Also, your mention of sexist culture makes it sound like that's the culture in technology startups, this is not true. Sexism, where it exists, does not depend on the domain. Its pervasive.
I disagree. Different domains have different women:men ratios and that'll affect the male sexism, particularly if the ratio is high on positions of power/influence.
Is there something that says females can't be inspired by males and vice versa? Why does anyone care a jot about the sex of a particular worker in their field when it comes to being inspired and encouraged?
Sounds like sexism to me.
Ding ding ding, exactly right. Not only that, but it takes a(n at least minimally) sexist culture for "sexist jokes" to be excused as "jokes" rather than acknowledging the real impact that they have for people. It's not just sexist jokes, it's any sort of off-color joke that's not appropriate in any sort of business/professional/even entrepreneurial setting.
Lesser ability [1], risk aversion and intolerance (on the part of women) are distinct possibilities. There is quite a bit of evidence supporting each of them. See both my comment and keithflower's reply, which presents additional evidence in favor.
http://news.ycombinator.com/item?id=3452963
[1] I'm pushing the Larry Summers' hypothesis of higher variance here, not an unequal mean theory.