fertility drops much below 2.1 babies per woman, the population will shrink unless offset by immigration.

Another reason for the falling birth rate is more complex: Raising children takes more effort than it used to.

Economic challenges are often cited as the reason why Millennials aren’t having children.

With birth rates in the U.S. in freefall,

Given that childcare costs have far outpaced inflation, the lack of paid parental leave and the high cost of childcare may be key reasons behind the birth rate decline.

There is another big caveat: Millennials are not having children at anywhere near the rate Gen X’ers and Boomers did, and Gen Z is poised to continue that trend.