In the late game, after all puzzles have been completed, I train everyone first in science, apart from a few that have inherited building from their parents. Once they've become a master in science I'll switch the girls to parenting. Even if the village is full up, they will still go around kissing the boys and gaining parent skills. When they are masters in parenting I'll put them on farming.
The boys I'll generally put on farming after becoming master scientists apart from a few I'll train first as doctors. Once they are master doctors I'll train them as farmers.
The few with building skills tend to take longer. After they've become master builders I'll train them as scientists then as farmers, or vice versa.
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To err is human; to arr is pirate.