One of the problems that worries people is that people live longer and longer and if fewer children are born the average age of the population will increase. That means that there will be more and more old people that don't work and likely require extra care therefore reducing the amount of normal workers even more.

Will society survive? Yes, obviously but it could probably have so severe consequences for people, and the countries.

A bit old, but still

Several evaluations suggest that policies that provide financial support to families or paid leave at the time of childbirth have a positive, but rather limited, impact in fertility. Of all the policies introduced over the years, provision of childcare services appears to be the most effective in encouraging families to have children and women to remain in the workforce.

French family policies provide a diversified system of supplementary resources in the form of money, time and services needed to raise children. The State provides support to diversified types of families with children at ages from early to late childhood. Another key ingredient has been the high stability of family policies, based on strong popular support. This stability gives confidence to families that they will benefit from continuous support from the birth of a child until entry into the school system and beyond. Such confidence creates a favourable environment for the decision to have children

https://www.un.org/en/development/desa/population/events/pdf/expert/24/Policy_Briefs/PB_France.pdf

Ménage à trois probably.

Hmm, I was thinking "well, that's an improvement, but still too high".