"We've been sold this bill of goods that we're in an era where people can be sexually free and participate equally in the hookup culture," Justin Garcia, an assistant research scientist at Indiana University's Kinsey Institute for Research in Sex, Gender and Reproduction, told The New York Times.
"The fact is that not everyone's having a good time," he said.
A study Garcia led involving 600 college students found women were half as likely to reach orgasm from intercourse or oral sex in hookups as they were serious relationships.
The study, with researchers Sean Massey, Ann Merriwether and Susan Seibold-Simpson of the State University of New York at Binghamton, was presented to the International Academy of Sex Research and the Association for Psychological Science this year and reported in the Times Tuesday.
"Women are not feeling very free in these casual contexts to say what they want and need," New York University sociologist Paula England told the Times.
England, who led a separate study of 24,000 students at 21 colleges over five years, found about 40 percent of women had an orgasm during their last recreational-sex encounter involving intercourse, while 80 percent of men did.
By contrast, about 75 percent of the women in the survey said they had an orgasm the last time they had sex in a committed relationship.
Part of the problem is that women may still feel a stigma for desiring physical pleasure without emotional bonding, England said.
Vanessa Martini, 23, from Marin County, Calif., told the Times she quickly learned most men she slept with casually didn't figure out what she wanted in bed.
"I haven't hooked up with anybody who was so cavalier as to just, like, not even care," she said. "But I think most of them were somewhat baffled that it would require more than just them thrusting."
Martini said most popular cultural depictions of sex that she'd seen didn't depict much reality.
"The way we view sex in porn and in movies and in books, people aren't talking to each other like, 'Oh, my foot's falling asleep, we need to move,'" she said.
At the same time, filmmaker Kim Huynh, 29, of San Francisco, told the newspaper when she was in college she consciously sacrificed orgasms for other no-strings-attached sexual benefits.
"As far as my ability to climax consistently, that's something I was able to have in my monogamous relationships," which she didn't have in less committed relationships, she told the newspaper.
But Huynh was willing to accept second-rate sex "for the freedom to be able to enjoy it all," she said.