For centuries, global differences in alcohol intake between men and women have been striking, with men consistently drinking several times as much as women.

The alcohol gap is a case of gender more than sex. Females and males metabolize alcohol somewhat differently, but the differences far exceeded any physiologic basis. Sharon and Richard Wilsnack, in the department of psychiatry and behavioral science at the University of North Dakota, wrote a comprehensive book on gender and alcohol in 1997, and according to them, differences in alcohol use have been central to societies’ symbolizing and regulating gender roles.

“Gender differences in alcohol consumption are found everywhere, to such an extent that they can be considered one of  the few universal gender differences in human social behavior,” wrote researchers from Finland’s Alcohol and Drug Research Group in 2004. The Wilsnacks said as much again in 2009 after leading an international research collaboration on gender and alcohol in 35 countries: “More drinking and heavy drinking occur among men, more long-term abstention occurs among women, and no cultural differences or historical changes have entirely erased these differences.”

So it’s an important and unprecedented turn that today in the journal BMJ Open, researchers from Columbia University and Australia’s University of New South Wales report that the alcohol gap is all but closed among young adults.

In an analysis of four million people between 1948 and 2014 across 68 international studies, the team found a clear and dramatic downturn in the male-to-female ratio of alcohol use. Men born between 1891 and 1910 were 2.2 times as likely as women to drink alcohol; among people born between 1991 and 2000, that ratio fell to 1.1. (Alcohol abuse in men has not significantly decreased over time, so the study implies that rates among women have risen.)

The same applies not just to alcohol intake, but in alcohol-related harm (alcohol misuse or dependence, alcohol-related problems and treatments, et cetera). A century ago, men were  three times as likely as women to have a drinking problem. Among people born in the 1990s, the odds are essentially the same for men and women.

The closure of this alcohol gap seems to be a result of other gaps closing, like the percentage of women working outside the home—an unintended negative health consequence of social progress. “When women improve their education, employment, and status,” according to Sharon and Richard Wilsnack, “they are likely also to have more opportunities to drink.”

Team Wilsnack has also found that later age at childbearing seems to be driving generational increases in alcohol consumption.

Today’s results have implications for targeting alcohol-abuse prevention and intervention. The researchers note that “alcohol use and alcohol-use disorders have historically been viewed as a male phenomenon,” but this study challenges such assumptions and suggests that young women in particular should be the target of concerted efforts to reduce the impact of substance use and related harm, calling particular attention to people born in the 1990s.

“Given that this young age group are relatively early in their alcohol-use careers,” the researchers write, “these findings highlight the importance of further tracking young male and female cohorts as they age into their 30s, 40s, and beyond.”

One recent study of generational changes in female drinking over three decades found that the daughters of 1,053 mothers had more than five times the odds of heavy drinking that their mothers had at the same age.

The list of things that are man problems is shrinking to those that involve the prostate and masculinity itself. And, of course, drinking is still a problem for men. As the Wilsnacks posit, “If women’s education and employment improve, what will happen to men’s drinking? If improvements in women’s roles threaten the self–worth of some men, or if women have better employment opportunities than men do, will changes in women’s roles increase risks of problem drinking among men?”

If excessive drinking is no longer the domain of masculinity, then maybe not. If pounding brews loses currency in that sphere, maybe guys pick up something new to define themselves. And hopefully that thing isn’t more smashing their heads together. I don’t know what it is, though. There’s probably room to safely do more in the realm of talking about one another’s balls, and how big and spherical they are.