I believe one way is to generate a frequency similar to female wingbeat frequency that attracts male mosquitoes and separate them that way. I am unsure if there is a difference in the frequency between genders.
There absolutely is a difference in sound. If you hear a mosquito, it's female. Males are silent.
This is how the photo fence from intellectual ventures detects and destroys female mosquitoes.Unfortunately they never released that tech as open source
Lesbian mosquitos...hello?
As long as they're inclined to seek out females in the wild and spread the mosquito STD, they could be just as useful as males :)