There are fears that a significant portion of people born in the US since the mid-1990s will not have married by the time they reach 40.

In a new paper for Demography, researchers Deirdre Bloome and Shannon Ang “project steep declines” in the probability of ever marrying.

They also predict declines that are larger among Black people than White people. If the most pessimistic models are correct, fewer than a quarter of blacks born in 1997 might get married by middle age.

The authors also offer some analysis of why the racial gap exists and why it matters. People from poorer backgrounds tend to marry less—a gap the authors also predict will grow—and blacks are disproportionately from poorer backgrounds; however, only a small share of the racial gap is explained by socioeconomic backgrounds.

More common explanations include a relative lack of employed “marriageable” males, higher rates of interracial marriage for black men, higher incarceration rates, and “exclusion from the physical spaces and social networks where many people find partners”.