Crossing Which Boundary? New Evidence on Racial and Educational Assortative Mating among Recent Different-Sex and Same-Sex Marriages

Abstract

This study revisits the question of “who marries whom” by examining detailed patterns of racial and educational assortative mating across newlywed different-sex and same-sex couples in the United States. Against the backdrop of growing racial diversity, driven largely by recent immigration from Latin America and Asia, and the expansion of higher education, including graduate degrees, the author asks what boundaries are being crossed and for whom. Using nationally representative couple-level data from the 2013 to 2023 American Community Survey, the author found that same-sex newlyweds, particularly male couples, were more likely to be interracial and educationally heterogamous than different-sex couples, with educational crossing more prevalent. Detailed pairing further reveals that White-Hispanic and, to a lesser extent, White-Asian unions primarily accounted for higher interraciality among same-sex male couples. Among same-sex couples, educational heterogamy often involved pairings among those with at least some college experience, such as bachelor’s and graduate degree pairs. These findings underscore how structural demographic shifts are reshaping new marital sorting and call for moving beyond binary measures of homogamy to capture how much, which, and for whom boundaries are crossed in the ongoing study of “who marries whom.”

Globally, marriages have become increasingly likely to cross racial/ethnic and educational boundaries (Esteve et al. 2016; Lundquist, Lin, and Curington 2024), with implications for both economic inequality and symbolic distance at interpersonal and societal levels (Alba 2020; Lichter and Qian 2019; Schwartz 2013). Yet most research treats racial and educational pairings as binary outcomes, obscuring which boundaries are crossed, and for whom.

Two major demographic shifts call for a reassessment using detailed racial and educational categories in the United States. First, post-1965 immigration has made the United States increasingly diverse, driven largely by Hispanic and Asian immigrants (Lundquist et al. 2024). This diversification suggests that contemporary interracial marriages may increasingly involve Hispanic or Asian partners. Second, the expansion of higher education has raised the share of adults with bachelor’s and especially graduate degrees, complicating the “college versus noncollege” divide with finer distinctions of “bachelor’s versus graduate degrees” (Posselt and Grodsky 2017).

Same-sex marriages add another important but understudied layer. Recent analyses from large, representative datasets show that same-sex marriages are more likely than different-sex marriages to cross both racial and educational lines (Hirschl, Schwartz, and Boschetti 2024; Manning, Westrick-Payne, and Gates 2022; Silva and Percheski 2024). However, these studies also rely on binary indicators of homogamy versus heterogamy. Reliable national data on same-sex marriage have been available only since 2013, when the U.S. Census Bureau began identifying same-sex couples systematically after the repeal of the Defense of Marriage Act (Gates 2015; Goodnature 2021).

Using couple-level data from the nationally representative American Community Survey (2013–2023), I analyze newlyweds, that is, those married within the past 12 months, to minimize bias from selective dissolution in longer marriages. The sample included both first and remarriages (see the Supplementary Information for a detailed description of data and measures, analytical strategy, and limitations, including robustness checks).

Figure 1 presents weighted percentages of racial and educational pairings across couple types. The two panels offer complementary views: the left summarizes overall homogamy versus heterogamy, while the right disaggregates specific pairings to reveal which boundaries are more rigid or permeable. For racial pairings, same-sex newlyweds, particularly male couples (30 percent), were more likely to be interracial than different-sex counterparts (15 percent). Consistent with demographic change, most interracial marriages involved White-Hispanic pairs and, to a lesser extent, White-Asian pairs among male couples. White-Black marriages remained comparatively rare (Alba 2020). Across all couples, White-White marriages remained the modal category.

Figure 1.

Racial (top) and educational (bottom) assortative mating among newlywed different-sex, same-sex male, and same-sex female couples, by binary (left) and detailed (right) pairings.

Crossing educational boundaries was more common than racial crossing. Same-sex newlyweds were also more educationally heterogamous than different-sex ones (49 percent), particularly for male couples (59 percent). Although “high school–some college” pairs remained common across all couples, same-sex couples more often involved crossings among those with at least some college experience, such as “bachelor’s degree–graduate degree” pairs, reflecting sexual minority individuals’ higher average education (Mittleman 2022). Modal pairings were “high school–high school” for different-sex couples, “some college–bachelor’s degree” for same-sex male couples, and “high school–some college” for same-sex female couples.

In this era of growing racial diversity and expanding higher education, newlyweds cross different types of boundaries depending on couple sex compositions. Boundary crossing among same-sex couples, particularly those involving Hispanic or Asian partners and individuals with graduate degrees, highlights how structural change and social identity intersect to shape emerging marital trends. Alba (2020) viewed ethnoracially mixed families as agents in redrawing group boundaries and expanding the American mainstream. The present analysis echoes this potential but also reveals variation in boundary permeability across detailed racial (and educational) categories. Future work should move beyond binary measures of homogamy to embrace heterogeneity in racialization histories, educational stratification, and sexuality, offering a fuller picture of how much, which, and for whom boundaries are crossed in the ongoing study of “who marries whom.”

Supplemental Material

sj-docx-1-srd-10.1177_23780231251395469 – Supplemental material for Crossing Which Boundary? New Evidence on Racial and Educational Assortative Mating among Recent Different-Sex and Same-Sex Marriages

Supplemental material, sj-docx-1-srd-10.1177_23780231251395469 for Crossing Which Boundary? New Evidence on Racial and Educational Assortative Mating among Recent Different-Sex and Same-Sex Marriages by Haoming Song in Socius