Millions of people first met their spouses through online dating. How have those marriages fared compared with those of people who met in more traditional venues?

Pretty well, according to a new study. A survey of nearly 20,000 Americans reveals that marriages between people who met online are at least as stable and satisfying as those of couples who first met in the real world —possibly more so.

John Cacioppo, a psychologist at the University of Chicago, wondered how online dating has changed American family life.

A scientific adviser to, one of the largest online dating sites, Cacioppo arranged for the company to pay for an online survey. Nearly half a million people received an e-mail questionnaire, and from the nearly 200,000 who responded, 19,131, all of whom got married between 2005 and 2012, had their replies analyzed.

For participants who were still married, the questionnaire included questions that social psychologists use to assess relationships. For example, respondents were asked, “Please indicate the degree of happiness, all things considered, of your marriage.”

Cacioppo asked two statisticians with no connection to eHarmony, Elizabeth Ogburn and Tyler VanderWeele of the Harvard School of Public Health, to analyze the answers. Officials at eHarmony also agreed that the study would be published no matter what the results revealed about online dating.

More than a third of the selected respondents reported meeting their spouse online. About half of that third met through online dating; the rest met through other venues such as chat rooms, games and virtual worlds.

The online marriages were durable. In fact, people who met online were slightly less likely to divorce and scored slightly higher on marital satisfaction. After controlling for demographic differences between the online and real-world daters, those differences remained statistically significant, the researchers reported in the Proceedings of the National Academy of Sciences.

Harry Reis, a psychologist at the University of Rochester, had a mixed reaction to the findings.

“They did control for demographic factors,” he said. “But they did not control for personality, mental health status, drug and alcohol use, history of domestic violence, and motivation to form a relationship.” All of these factors are known to affect marital outcomes, he said.

“It is entirely possible that when these factors are taken into account, online meeting may have worse outcomes than offline meeting,” Reis said.

ScienceNOW is the daily online news service of the journal Science.