Are there any master breeders? Are there any benefits to being a master breeder?

I noticed that I can make the villagers become trainee parents pretty easily (a female villager is usually trainee before her first pregnancy). But after that, it's hard to advance the skill bar because she will have babies in about 3 tries or so. Even if I keep her nursing all the time, she still wouldn't reach master level by the time she dies.

Hmmm ... maybe I should try and see if I can make a master breeder out of a male villager .... males do not have the two year nursing time out. hee hee .....