is there a way where people can earn parenting skills without me manually getting to do things.

Yes, but it's not as dependable. If you set a villagers preferance to parenting, and help them to trainee status, they will go around practicing.
2 problems, 1) they will practice with anybody of the opposite sex and 2) they only practice when they're in the mood.

If you're only wanting to build your population, you can set the preferance for some of the young women to parent and they'll work at it pretty consistently.

If you're wanting to build skills to get an elder, do it the hard way.