J Popul Econ (2002) 15:417–432 Assortativematingamongunmarriedparents: Implicationsforabilitytopaychildsupport IrwinGarfinkel1,DanaGlei2,SaraS.McLanahan3 1 School of Social Work, Columbia University, 622 W. 113th Street, New York, NY 10025, USA (Fax: þ1-650-321-1192; e-mail: ig3@columbia.edu) 2 O‰ce of Population Research and Center for Research on Child Wellbeing, Princeton University, 21 Prospect Avenue, Princeton, NJ 08540, USA (Fax: þ1-609-258-5804; e-mail: danaglei@princeton.edu) 3 Bendheim Center for Research on Child Well-Being, Princeton University, 21 Prospect Avenue, Princeton, NJ 08540, USA (Fax: þ1-650-321-1192; e-mail: Mclanaha@princeton.edu) Received: 31 May 2000/Accepted: 2 January 2001 Abstract. Assortative mating is of interest to both theoretical and applied so- cial scientists. Previous research is based almost entirely on married couples and parents. In this paper we use data from the NSFG to examine assortative mating among unmarried parents in the US and to examine the robustness of estimates of nonresident fathers’ income based on assortative mating assump- tions. We find that never married parents are similar, though not identical, to married parents in their choice of partners. White unmarried women are much more likely to have a child with a non-white male than white married women. On the other hand, unmarried women are more likely than married women to have a child with a more educated male. JELclassifications: H, I, J Keywords: Assortative mating, unmarried parents, child support 1. Introduction Assortative mating – the tendency of people to choose partners of similar age, race, educational attainment, and other social, psychological, and biological characteristics – is of widespread general interest to social scientists. It is an important empirical feature of the marriage market that theories of marriage seek to explain (Becker), an indicator of social distance or prejudice between groups (Bourdieu), and a mechanism through which di¤erences between so- All correspondence to Irwin Garfinkel. This research was supported by a grant from the National Center for Child Health and Human Development (5 R01 HD10375). We would like to thank Germa ´n Rodrı ´guez for his statistical assistance and two anonymous referees for helpful comment. Responsible editor: John F. Ermisch.