Both can be problems. The lack of housing just big enough for a single, maybe couple, with an occasional guest (friend/etc) that later becomes the first baby's room. The lack of overall social stability to promote relationships.

In more modern terms, also the lack of a home office for each working adult; because society still hasn't digested the possibility of remote-mostly working and how that can be a good thing, rather than the hell many are facing during this pandemic.