I'm really curious about dancers having babies. I remember reading stories about Balanchine forbidding his ballerinas from having babies. However, now I find that it is not highly unusual for dancers to be pregnant and then come back to dance. Balanchine hated to see his hard work go down the tubes if a dancer got pregnant. Now, we have companies that are not usually run by such a dictator.
Many companies allow maternity leave.
But it is hard. It means leaving the child and family for touring. Being gone at night and day. Having a family is not an easy thing for the female ballet dancer. He also would say he could not get attached to the dancers because they would eventually go off and have babies.