Summary
Wu pools retrospective marital and fertility histories from the June 1980, 1985, 1990, and 1995 Current Population Surveys (CPS) (201,033 women; 339,909 births) to produce cohort estimates of nonmarital fertility spanning ~50 years of U.S. experience. The paper demonstrates that nonmarital childbearing was already nonnegligible before World War II (WWII), rose monotonically across successive birth cohorts, and is not solely a teen phenomenon. Wu introduces the cohort nonmarital fertility ratio (CNMFR) as a cohort complement to the standard period nonmarital fertility ratio (PNMFR) used in official vital statistics.
Key Claims
- For women born 1925–1929, fully 1 in 10 had at least one nonmarital birth by age 30; the standard narrative of near-zero historical nonmarital fertility is incorrect
- For the 1965–1969 cohort, 1 in 4 all U.S. women had a nonmarital birth by age 30: ~1 in 5 white, ~3 in 5 black, ~1 in 3 Hispanic
- The proportion of women with a nonmarital birth roughly doubles between ages 20 and 30 for all cohorts of white and Hispanic women (+two-thirds for black women) — nonmarital fertility is not primarily a teen phenomenon
- White nonmarital births are ~2× more likely than black or Hispanic nonmarital births to follow marital separation/divorce (rather than to never-married women); a qualitative compositional difference, not just a level difference
- The CNMFR rose threefold from the pre-1925 to the 1950–1954 cohort for all women (6.3%→18.9%) and for white women (4.7%→13.0%)
- For black women, CNMFR rose from 16.4% (1925–1929) to 47.7% (1950–1954) — high absolute levels but similar proportional trajectory to white women
- U.S. near-replacement fertility rests partly on nonmarital births; policies aimed at reducing nonmarital fertility risk reducing overall fertility below replacement
- The period PNMFR from vital registers is subject to systematic bias from birth-certificate underreporting of marital status (missing in ~30% of 1968 births, ~40% of 1979 births) and from CPS sampling-frame exclusions
Concepts Introduced or Extended
Entities Mentioned
Quotes
"For women born between 1965 and 1969, more than 1 of 4 had one or more nonmarital births by age 30, with roughly 1 of 5 white, 3 of 5 black, and 1 in 3 Hispanic women having at least one nonmarital birth by age 30."
My Take
The CNMFR is a useful methodological contribution — the same logic that motivates cohort over period life expectancy applies here. The qualitative race/ethnicity difference (white nonmarital births concentrated post-separation vs. black nonmarital births concentrated to never-married women) is underappreciated and has implications for which policy levers are relevant. The policy paradox is real: the U.S. near-replacement fertility rate is not a neutral demographic fact but partly a product of nonmarital childbearing; reducing it requires careful accounting of substitution effects.