, Volume 42, Issue 2, pp 259–273 | Cite as

The age pattern of first-birth rates among U.S. women: The bimodal 1990s

  • Rachel Sullivan


Between 1990 and 2002, the age pattern of Type I first-birth rates (i.e., the hazard of a first birth) among U.S. women was bimodal. This pattern, driven by changing differential fertility patterns among racial and ethnic groups, reached its apex at the mid-1990s and had almost vanished by the decade’s end. Research on first-birth timing has tended to focus on Type II first-birth rates and therefore has failed to identify this larger, bimodal pattern. This article presents the benefits of using Type I rates, documents the emergence of the bimodal pattern via two new measures of bimodality, and uses a decomposition analysis to discuss the pattern’s causes.


Current Population Survey High School Degree Fertility Transition Bimodal Pattern Childless Woman 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Population Association of America 2005

Authors and Affiliations

  • Rachel Sullivan
    • 1
  1. 1.Graduate Group in Sociology and DemographyUniversity of California, BerkeleyBerkeley

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