There are one, maybe two, other events that can help, as well. One is a no-option event, and the other gives you a choice what to do.

No option event (highlight to view):
Another couple can fall down the waterfall, just as your villagers did at the start of the game. Gives you an adult male and adult female

Optioned event (highlight to view):
A Savage Child shows up - scare away or lure with food. If you lure with food, you get a child. For me it was a 13-year-old boy. But I think you can get a girl, too.