"The big finding in our study is that young men had a lot less knowledge about emergency contraception than the young women that we surveyed, and even among the young women, knowledge wasn't great," Sheree Schrager, a member of the study team, told Reuters Health.
"About half of the women understood basic facts about emergency contraception, how you get it, how you use it, and the fact that male partners were also able to buy it over-the-counter for their female partners," added Schrager, a researcher at Children's Hospital Los Angeles, California.
"But young men had significantly lower knowledge then the young women did, and this is an opportunity for providers to reach out to young men in the hopes of reaching more young women to use emergency contraception," she said.
Emergency contraception, sometimes called "the morning after pill," prevents pregnancy after unprotected sex or when barrier methods of contraception fail. Currently, nine U.S. states allow pharmacists to dispense emergency contraception without a prescription under certain conditions, according to the Guttmacher Institute.
Unplanned pregnancies happen at higher rates in poor communities, and their health and economic consequences may be greater, the researchers write in The Journal of Family Planning and Reproductive Health Care.
Levonorgestrel (Plan B) has been the primary agent used for emergency contraception since its introduction in 2000, they note. But it's promise for preventing up to half of unwanted pregnancies has gone unfulfilled, in part because of lack of knowledge and access to the drug.
To gauge how much older teens and young adults know about emergency contraception, the researchers enrolled 101 males and 97 females ages 18 to 25 into the study during 2008 and 2009. The participants were either patients at a free health care clinic in Los Angeles or had received physical screenings as part of their training for the Los Angeles Job Corps.
Most of the participants were Hispanic - about 61 percent. Another 13 percent were White and 16 percent were African American. The remaining 6 percent identified themselves as belonging to "other" ethnic groups. Almost three quarters had not completed high school.
About 36 percent of sexually experienced young women had used emergency contraception previously, while 18 percent of the sexually experienced males had partners who had used it.
The participants answered questionnaires that included items measuring their knowledge of facts about emergency contraception attitudes about using it. Composite scores were determined from the number of correct answers and ranged from 0 to 4.
The women's average score was 2.85, while the men's average score was 1.97.
About half the women and a third of the men knew that emergency contraception was available at pharmacies without a prescription.
Only 18 percent of the women and 8 percent of men knew that emergency contraceptives were available to women under the age of 18.
A few more men than women (26 percent versus 21 percent) knew that a man can purchase emergency contraception for his female partner.
"We also found that the young men and young women were really interested in learning about emergency contraception and other forms of contraception from their primary healthcare providers and so despite the fact they mostly get the knowledge from their friends, in the future they'd much rather be hearing about it from the doctor," Schrager said.
The findings might not apply to all young people, the authors point out.
"These were young people who are receiving medical screenings either because they were enrolled in job corps looking for training and education because they were attending Saban Clinic - a free clinic for young people who don't have money to access other kinds of care," Schrager said.
Schrager added that her group's report was targeted to healthcare providers who may have overlooked young men when thinking about pregnancy prevention in their practices.
"Physicians can do a good job of reaching out to not only to young women who could potentially get pregnant, but to their potential partners and it's another way to reach young women who may have been missed by someone else somewhere along the line," Schrager said.
Dr. Paula Adams Hillard told Reuters Health that the ideal way to educate young men about emergency contraception would be if all school systems provided comprehensive sexuality education.
Hillard provides pediatric, adolescent and adult gynecology services at the Lucile Packard Children's Hospital and Stanford Hospitals and Clinics in Palo Alto, California.
"It happens in some schools, but obviously not very many, and certainly not as many as we'd like," said Hillard, who is also a professor at the Stanford University School of Medicine.
"There are really excellent programs for sex and sexuality education through a number of organizations but they're outside the school systems," Hillard said. She pointed to an emergency contraception information website run by Princeton University.
Hillard said that as a gynecologist, she's always talking to young women, but also encourages them to talk to their partners about emergency contraception.
"There is a dedicated emergency contraceptive product that is now available to all ages over-the-counter, called Plan B One-Step, which is just one of several different emergency contraceptives, but it is available without a prescription over-the-counter to all ages," Hillard said.
A second study of contraceptive use published in the same issue of the journal looked at the possibility that pharmacists could play a bigger role in helping women gain access to effective contraception so they might avoid the need for emergency methods.
Dr. Lucy Michie of the Chalmers Sexual and Reproductive Health Centre in Edinburgh led the study that included 211 women who requested emergency contraception at one of nine pharmacies in January 2013.
The women were given questionnaires about their contraceptive use including ongoing and emergency methods.
The researchers found that a third of the women needed emergency contraception due to unprotected sex and half reported condom failure.
Of those women, about half expressed interest in starting ongoing contraceptive methods such as the birth control pill.
The women also said they would welcome it if during their visit to purchase emergency contraception, the pharmacist also provided a limited supply of The Pill, giving the woman time to make an appointment with her physician to find the right long-term contraceptive method for her.