There's always a chance...as was posted previously, the Barrel O' Babies or tightly sealed crate (sometimes those have a baby or two) events could bring you some males. You'll just have to wait for them to grow up.

There's also a CHANCE if you investigate/get a closer look at the "face in the trees" event, your villager won't disappear, never to be heard from again, but rather, you'll get a new adult villager who joins your group.

O' course, you gotta get the event first, so maybe put your game on 1/2 speed and see what happens? Good luck!