Once they get skill in parenting, they will put that practice to work. It's a "job" just like any other. When you get a scientist who is skilled in their work, they will continue to work on their own. So will your parent. Several players have decided not to train parents until their tribe can support the effects. What I suggest:
1. Let her continue until the tribe is maxed for your current level. She will continue to attempt "train", but she will no longer have children due to the max population.
2. Start her training on something else, such as scientist/farmer/etc. You'll have to keep an eye on her until she's at least a Trainee, (and possibly after) as she could wander off and try her old job again.
I hope this helps
