In Fahrenheit 451, the society promotes isolation, and looks down on any kind of family bonds. Therefore, close relationships are not encouraged, and women do not consider giving birth or raising children an important part of life. In one section, Montag listens to Mrs. Bowles, Mildred's friend, talk about how easy it was to give birth- simply schedule the Cesarean section for whenever fits your busy life. She also discusses how important the TV walls are in their lives. The assumption here is that those walls are raising her children, not her. It's clear that the births of her children are no more significant than the latest episodes of their favorite show. In fact, they seem to mean much less to her.
Again, this is because the society frowns upon close family relationships. This is why the McClellans are shunned. They don't watch TV; instead, they sit and talk together as a family. That is odd behavior inhe world of the novel, and it is what eventually leads to their eradication by the government.