I think the urge to have a baby is more than societal. It is instinctive. The female body is designed for childbirth, so it seems natural to me that women would experience a desire to have children at some point in their life. Although some may not. And I obviously can’t speak from experience. : )

We have (married) friends who never wanted, or had, children and are now in their 60s. Yet they hung out with us married with children people anyway. And still do, although our kids are all grown now.

I think it is far less common for single people to hang out with married people, especially once they have kids. It’s just a whole different lifestyle. And children require all of your time (in the beginning.) Making it harder to find time to “hang out” with friends.