University of Iowa researchers found that couples that became sexually involved as friends or acquaintances and were open to a serious relationship ended up just as happy as those who dated and waited.
"It's also possible for true love to emerge if things start off with a more 'Sex and the City' approach, when people spot each other across the room, become sexually involved and then build a relationship," said UI sociologist Anthony Paik.
However, relationships that initiated as hook-ups had a lower quality score - possibly because some people are prone to finding relationships unrewarding, and those individuals are more likely to form hook-ups.
"The question is whether it's the type of relationship that causes lower quality or whether it's the people," he said.
And the answer is that it's the people.
People with higher numbers of past sexual partners were more likely to form hook-ups, and to report lower relationship quality.
The research also showed that plenty of people date even if they aren't interested in a long-term relationship - surprising, since dating falls under the romance category, while "friends with benefits" and hook-ups do not.
"In the casual dating category, some people think they're headed for a long-term relationship, but there are also people who are only in it for sex. It basically brings 'players' and 'non-players' together," said Paik.
"As a consequence, it raises the question of whether casual dating is a useful institution. This paper would suggest not really, because it doesn't screen out the non-romantic types," he added.
The study is published this month in the journal Social Science Research.