In a couple of games where my population is maxed out I'm going for as many Elders as possible. Setting villagers to be parents is an essential part of the process, especially as it is virtually impossible to get a master builder once the various projects have been completed. A villager can advance to master parent fairly quickly if the population is at the maximum, even though few villagers actually get to be parents. That doesn't seem to stop them enjoying trying, though, judging by the constant chorus of kisses!

I would add that I only set female villagers to be parents when I'm trying to build up the village, never male villagers. Males are only trained to become parents once the village is maxed out.