It’s official: Sudden wealth makes you attractive—and it’s now backed by research.

Specifically, sudden wealth makes men, on average, more likely to marry and have kids and less likely to divorce. But with women, it’s different. On average, sudden wealth does not affect their likelihood of marrying or having kids. But it makes them much more likely to get divorced—fast.

So says a new study by researchers from New York University, Stockholm School of Economics, and the University of Barcelona who devised a novel way to test an economic theory that other economists have struggled to verify for decades.

Economists have long believed their field can help explain much of family life, including marriage, divorce, and having kids, a notion pioneered by Nobel Prize winner Gary Becker some 50 years ago. But obtaining the necessary data “has proven notoriously challenging,” the authors note. The main difficulty has been identifying large numbers of people who have experienced upward shocks to their incomes and then collecting non-economic data on them for years.

The authors’ solution? Study players of Swedish lotteries.

Prizes range from small to large, and, as in any lottery, winners are chosen randomly, “effectively replicating the conditions of a randomized control trial,” the authors say. They then created large samples of lottery winners and non-winners from publicly available sources and merged them with government data, including income, marriages, divorces, and births.

The results for men are dramatic. An unmarried man who wins a lottery prize of about $96,000 (1 million Swedish kronor) is 30% more likely to get married in the following five years and, if married, is 40% less likely to get divorced in the next 10 years. Married or not, men, on average, have 14% more children in the following 10 years.

By contrast, a lottery win affected women in just one statistically significant way: It almost doubled their short-run probability of getting divorced. Researchers note that because the effect is visible only in the years immediately after the lottery win, a possible interpretation is that wealth accelerates divorces already underway.

The new research defies at least one conventional view: the widely held notion that young adults postpone marriage until they reach financial stability. If that were true, the marriage rates of low-income women would rise after a lottery win, but they don’t.

The research also reinforces some traditional beliefs. In line with separate academic findings and centuries of conventional wisdom, “wealth appears to improve the marriage market prospects of men more than women, on average,” the researchers observe. If that’s because men and women value different criteria when choosing a mate, they carefully note, it would fit with “literature indicating that women value earning potential, intelligence, and social status of potential partners more than men do.” But the researchers do not claim their results prove this.

Not surprisingly, the effects of lottery wins on both genders are greatest among those with low incomes.

Because the researchers solved critical problems in gathering data, their new study shows with extraordinary power and specificity how family economics can profoundly alter the non-economic lives of men, women, and children. Perhaps the old saying “It’s only money” should not be spoken so dismissively.