But that could change. An injectable contraceptive — the latest in a series of forays into birth control for people with penises — proved highly effective at preventing pregnancies in a new study published in the Journal of Clinical Endocrinology & Metabolism. Despite various side effects — including mood disorders, acne and erectile dysfunction — a majority of the participants were happy with the birth control method, and said they'd use it if it were available.
Related: History and evolution of birth control
The evolution of birth control
The evolution of birth control
Closeup still life of Zorane tablets, a series of low-estrogen birth control pills. Shown are three packs, one open, two closed. (Photo by Hulton Archive/Getty Images)
Various big posters were hoisted in Saint Peter's Square by a group of persons favoring artificial birth control, as Pope Paul VI appeared in the central balcony of Saint Peter's Basilica to read his Easter message to the world and impart his blessing "Urbi et Orbi" (Over the City of Rome and the World) March 26, 1967. The huge poster in center reads: "Yes to the pill", while others read: "No to Abortion." (AP-PHOTO)
13th August 1968: Father Paul Weir expounds on his refusal to quit the Catholic church in the St Cecilia Presbytery in North Cheam. Father Paul, 31, was suspended from his duties because he disagrees with the Pope's ruling on birth control. (Photo by Keystone/Getty Images)
Birth control advocate Bill Baird, center, and Carol Morreale, left, as they led a demonstration outside the Immaculate Conception Church, Aug. 18, 1974 in Marlboro, Mass., protesting the denial of the baptismal sacrament to 3-month-old Nathaniel Morreale. Carol Morreale, the child's mother has publicly advocated that women be given the right to choose whether they will have an abortion. (AP Photo)
A woman holds a birth control pill dispenser indicating the day of the week in New York in August 1974. Though medical trials for the oral contraceptive started in the late 1950s, Enovid was approved by the Food and Drug Administration in 1960. The sexual revolution was born. Known as "The Pill," it changed the balance of hormones estrogen and progesterone in women to prevent pregnancy. It was invented by Dr. Gregory Pincus and Dr. John Rock with the support of Planned Parenthood founder Margaret Sanger. (AP Photo/Jerry Mosey)
FILE - This May 28, 1999, file photo shows a new birth control pill container designed to look like a woman's makeup compact for Ortho-McNeil Pharmaceutical Inc., of Raritan, N.J., displayed at the manufacturer's assembly line. More than half of privately insured women are getting free birth control due to President Barack Obamaâs health care law, part of a big shift thatâs likely to continue despite the Supreme Court allowing some employers with religious objections to opt out. (AP Photo/Mike Derer, File)
Graphic shows the Implanon implant, with contraceptive use stats among women ages 15-44. (AP Graphic)
Graphic shows preferred method of birth control for women by age; 1c x 3 1/2 inches; 46.5 mm x 88.9 mm
Chart shows failure rate of popular female contraceptives
Graphic shows the annual cost of the most effect birth control methods
Individually packaged hand-knitted uteri are placed on a countertop at the lobby of the State Capitol in Phoenix, Thursday, April 5, 2012. Critics of an Arizona proposal to limit birth control gave more than a dozen state lawmakers the personalized gift. The packages were delivered each in a clear plastic bag, labeled with a lawmakerâs name and containing a letter from a Tempe woman asking legislators to oppose the measure. (AP Photo/Terry Tang)
FILE - In this May 2, 2013 photo, pharmacist Simon Gorelikov holds a generic emergency contraceptive, also called the morning-after pill, at the Health First Pharmacy in Boston. The plaintiffs in a legal battle over emergency contraceptives say in a letter Wednesday June 12, 2013, the government has failed to comply with a New York judge's order to lift all restrictions on sales of the drug. (AP Photo/Elise Amendola, File)
A group of people organized by the NYC Light Brigade and the women's rights group UltraViolet, use letters in lights to spell out their opinion, in front of the Supreme Court, Monday, March 24, 2014, in Washington. Holding the "H" in "Hands" is Rep. Keith Ellison, D-Minn. The Supreme Court is weighing whether corporations have religious rights that exempt them from part of the new health care law that requires coverage of birth control for employees at no extra charge. (AP Photo/Alex Brandon)
Margot Riphagen of New Orleans, La., wears a birth control pills costume as she protests in front of the Supreme Court in Washington, Tuesday, March 25, 2014, as the court heard oral arguments in the challenges of President Barack Obama's health care law requirement that businesses provide their female employees with health insurance that includes access to contraceptives. Supreme Court justices are weighing whether corporations have religious rights that exempt them from part of the new health care law that requires coverage of birth control for employees at no extra charge. (AP Photo/Charles Dharapak)
(Photo via Getty)
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"The study found it is possible to have a hormonal contraceptive for men that reduces the risk of unplanned pregnancies in the partners of men who use it," researcher Mario Festin said, according to the BBC.
How it worked: The injections contained the hormones progestogen and testosterone, and researchers aimed to see whether they could reduce subjects' sperm concentration enough to effectively prevent pregnancy.
Because people with healthy male reproductive systems constantly produce sperm, it tends to take high doses of hormones to get a person's sperm count down to 1 million per milliliter, according to the BBC. In past birth control trials, excessive hormone levels have caused men to break out, put on weight and experience prostate and liver problems.
To conduct their study, researchers recruited "healthy men, aged 18 to 45 years, and their 18- to 38-year-old female partners, both without known fertility problems," according to the study. The men were injected every eight weeks.
The results: After 24 weeks, 96% of participants had sperm concentrations less than or equal to 1 million/mL. Over the course of 56 weeks, just four pregnancies occurred among the partners of 266 men. The researchers also found the suppression of sperm creation to be reversible.
"The study regimen led to near-complete and reversible suppression of spermatogenesis," the researchers concluded. "The contraceptive efficacy was relatively good compared with other reversible methods available for men."
It's promising, but not perfect: Side effects caused 20 men to drop out the study early.
Of these 20, six men discontinued only for changes in mood, and six men discontinued for the following single reasons: acne, pain or panic at first injection, palpitations, hypertension and erectile dysfunction. Eight men discontinued for more than one side effect, including multiple reasons related to changes in mood.
Due to the risks of mood changes, depression, pain and decreased libido, the researchers stopped taking on new study participants in 2011.
Nevertheless, 75% of participants said they were "at least satisfied with the method and willing to use this method if available, which supports further development of this approach."