Why does Lily want to be a birthmother?

Lily wants to be a birthmother because she thinks newborns are cute. She also likes the fact that birthmothers are well fed and don't have to excercise.

“I think newchildren are so cute,” Lily sighed. “I hope I get assigned to be a Birthmother.”

".... she told me that the Birthmothers get wonderful food, and they have very gentle exercise periods, and most of the time they just play games and amuse themselves while they’re waiting. I think I’d like that,” Lily said petulantly.