These are one of the few studies that aren't based on online dating that are being used to prove the existence of hypergamy in our current day.
Data were drawn from the 2002 and 2011–2013 National Survey of Family Growth, a US probability-based household survey focusing on sexual and reproductive health. The measures included in this analysis were lifetime opposite-sex sex partners and opposite-sex sex partners in the past year...
This study examined Black and Latino adolescents - arguably one of the two most poverty-stricken groups in America, so risk potential is high in this sample already.
Second, it is found that a smaller group of men are having sex. I see this as education levels rising and risk behavior declining.