The share of U.S. adults reporting no sex reached an all-time high last year, according to the latest data from the General Social Survey. Nearly 23 percent of adults between the ages of 18 to 29 were celibate in 2018, more than double the number since 2008. The data underscores a three-decade trend, marked by an aging population and higher numbers of single people. One surprising result from the data was that a much larger than expected number of the sexless individuals were men. For most of the past three decades, men and women in their twenties reported similar rates of sexlessness. Since 2008, however, the share of men younger than 30 reporting no sex has nearly tripled—compared to an eight percentage point increase reported among females of the same age group.

There are several theories as to why more young men are sexless than their female counterparts. One explanation is that labor force participation by young men has dropped, and researchers see a “connection between labor force participation and stable relationships,” according to Jean Twenge, a professor of psychology at San Diego State University who writes about Generation Z. Other explanations are that young men are more likely to live with their parents, and technology’s affect on men. “There are a lot more things to do at 10 o’clock at night now than there were 20 years ago,” Twenge said.