You say this as if the fields themselves decided, but it could just as easily be that women pushed in harder.
> Fifty years ago people would no doubt have told you that women just weren't interested in becoming lawyers or doctors.
Again, what was the difference? You've suggested a relative difference in sexism at the time, but I've seen no data suggesting this. It just looks like a guess on your part.
> You don't, either.
Why would you even say this? The comment you responded to didn't have me asserting a reason why. It's like you're attacking a strawman.
I claimed that this is the case today. You are the only one of us making any assertions whatsoever about levels of sexism in the 1960s and 1970s, which are irrelevant to choices women make now.