In my past life as D.O. for a 125 hauling the Wall Street Journal around the U.S. and as well as a little freight out of FLL around the Caribbean and Bahamas, in CV, 3's, 4's, & 6,s.
We had two female FE's one super based at STL and one total trainwreck at FLL. We also had 4 female pilots. Two great, with one to saving the CV440 (on fire!) while the captain screwed the pooch and two not so good. I'd say they were pretty much on par with their male crewmates. That was 15 years ago when I think the product coming out of the flight schools was vastly superior to most of the graduates I encounter now. Almost anyone can be taught to pilot a plane but there are only some of either sex that make a good manager" Captain".