Public Health On Call 990 - Is There a Fertility Crisis?
Jan 5, 2026
In this discussion, Linnea Zimmerman, an associate professor at Johns Hopkins with expertise in fertility and contraceptive access, analyzes the U.S.'s record low birth rate. She explains the complexities of measuring fertility and trends worldwide, highlighting differences between regions. Zimmerman challenges the notion of a fertility crisis, addressing societal impacts, and the role of migration. Economic pressures and gender dynamics influencing family size desires are also examined, alongside how policy changes could empower individuals to align their choices with desired family sizes.
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Period Versus Cohort Fertility
- The U.S. total fertility rate is a period measure reflecting births now, currently about 1.6 children per woman.
- Cohort fertility counts children by end of childbearing and can differ if births are merely delayed.
Teen Birth Declines Affect Short-Term Rates
- Falling teen births can suppress the period fertility rate even if women later have the same number of children.
- Current low period rates may reflect delayed births rather than permanently fewer children.
Huge Global Fertility Variation
- Global fertility is falling but varies widely from under 1.0 to over 6.0 children per woman across countries.
- The global average remains about 2.2–2.3, still above replacement.