Given that we live in a very male dominated world and the senior pilot ranks are full of good ole boy carry overs from a previous era, I'd imagine that any female that has risen through the ranks to become a pilot/FO has more than proven her stuff. I'd think that since she's under the microscope with people looking at things to criticize she probably has to do it better than her "average" male colleague.
It wouldn't bother me for a single second to see a female at the front (nor for that matter a black or an Asian [unless it's KE
and then all bets are off] or a . . . . .). Pilots have to prove themselves to exceedingly high standards - standard which are colorblind and gender neutral. If they pass, that's good enough for me.
Now, male flight attendants make me uncomfortable - but that's another story.