Thanks for that answer. I'm still trying to figure out how to plan effectively for a tribe. I have another villager who was a master of farming, building and research when he became elderly and I granted him youth. He is probably in his 40's now, still trying to master healing, so I'm not sure if the problem is with all skills, or if no one really likes to study medicine. I'm certainly having to put student healers back in that area constantly.