Since the U.S. Supreme Court overturned Roe v. Wade in 2022, many have wondered if the same legal logic that led to abortion bans could eventually be extended to female contraception. Already, some lawmakers have set the stage: back in July 2022, all but eight House Republicans voted against a bill that would codify the right to contraception. The vote took place amid concerns that the Supreme Court might overturn a decades-old ruling prohibiting states from banning contraceptives.
Fear and speculation in this regard has led to more American males getting vasectomies, as there is not a male equivalent to female contraceptive drugs like hormone-based birth control.
Indeed, currently the only medical options for male birth control are vasectomies and condoms. Yet that could soon change, as researchers in the medical community have been slowly making progress on male birth control methods that are more akin to those offered to women — meaning shots or pills that would temporarily and reversibly render men infertile.
When the mice were paired with females to mate, zero pregnancies occurred. Nearly three hours later, the sperm began to move again. And nearly a day later, they resumed normal activity.
Unlike previous proposals for male birth control methods, the latest one could work on-demand and restore fertility within hours. The results from testing, which were published in Nature Communications, introduced the concept of male birth control that involved administering a compound called TDI-11861. In the study, the researchers injected 52 male mice with the experimental compound, which temporarily inhibited an enzyme called adenylyl cyclase (sAC), which helps sperm move. When the mice were paired with females to mate, zero pregnancies occurred. Nearly three hours later, the sperm began to move again. And nearly a day later, they resumed normal activity.
"The on-demand strategy we validate here, where a man will be temporarily infertile shortly after taking a single dose of a contraceptive agent, is qualitatively distinct from all other existing pharmacologic methods as well as known efforts to develop a male contraceptive," the researchers noted.
Melanie Balbach, a lead scientist on the study, told Salon that the idea of targeting the enzyme started two decades ago in her lab. Dr. Lonny Levin and Dr. Jochen Buck, co-authors of the study, discovered the potential of the protein.
"What they found was that as soon as the mice are missing that enzyme, they are infertile, and that means that the enzyme plays a crucial role for the fertility of the sperm,"Balbach said. "The problem was then that they found that that protein or that enzyme was not only in sperm and in the testis, slowly, they actually found it everywhere in the body, and back then the dogma in the field was that to develop a male contraceptive that is safe, it needs to be only in the male germline because otherwise they were afraid that there will be too many side effects."
Researchers set about to study what the protein or enzyme did in the human body. Finally, a few years ago, a study found that two human males who were missing the enzyme completely were infertile, but otherwise perfectly healthy. This reignited the idea that this could be a viable potential male birth control.
A study for a promising hormonal male contraceptive in 2016 was halted because of side effects like extreme acne and mood disorder; notably, these are side effects that are often experienced with female hormonal contraceptives.
This isn't the first time a pharmaceutical-based male birth control contraceptive has been touted and tested. As Salon reported in March 2022, research presented at a meeting of the American Chemical Society showed that a contraceptive compound called YCT529 made male mice temporarily impotent. During the trial, the male mice were given the pill everyday. Within four weeks it was observed to be 99 percent effective at preventing pregnancy in the female mice. However, four weeks after the male mice stopped receiving YCT529, they were able to impregnate the female mice again.
Previous trials into comparable male contraceptives have failed to catch on due to potential side effects. For example, a study for a promising hormonal male contraceptive in 2016 was halted because of side effects like extreme acne and mood disorder; notably, these are side effects that are often experienced with female hormonal contraceptives.
However, with both studies in mice that target enzymes instead, side effects have been minimal. What is unique about Balbach's study is how fast it could potentially work in human males.
"It can be an on-demand approach and doesn't have to be chronic, meaning the men would take the inhibitor everyday like they have to for a hormonal pill," Balbach said. "That will also help to strongly reduce any potential side effects that could occur."
But there are more steps to take before such a drug could be sold on the market. Balbach said they are working on testing the approach on rabbits, and then will have to move to a human trial, which could take six to eight years.
Balbach added: "We are not planning to develop the exclusive male contraceptive, so we hope we will be one option out of many options and that men actually can choose whatever they want."
