Male Birth Control Working On Rabbits, Humans Are Next

• Vasalgel, a reversible injection, blocked sperm in pre-clinical trials in rabbits.
• Male birth control pills have shown efficacy in animals.
• We’re closer to viable male birth control, but a human version is still years away.

Male birth control may be years out, but there are pills and injections in the works that are already stopping the flow of sperm in trials. These new methods tout all the orgasm without all the mess (and babies).

Several outlets are hailing Vasalgel, a reversible form of birth control that blocks the flow of sperm after being injected into the vas deferens, the duct that brings sperm from the testes to the urethra. But it's way too early to celebrate -- the polymer injection is in pre-clinical trials and has only been successfully administered to 12 rabbits. Still, the results, released on Tuesday, are promising.

Vasalgel is meant to serve as an easily reversible replacement for vasectomy. Rather than severing the vas deferens, as doctors do for vasectomy, Vasagel would be injected to create a gel barrier for sperm. (Vasalgel appears to have no effect on orgasm or ejaculation, and even though sperm is blocked, seminal fluids can still be released.)

When a man wants to reverse the process, a second injection would dissolve the polymer and open the vas deferens for business.

Clinical trials in humans should take place later this year, according to a press release by the Parsemus Foundation, which developed the contraceptive. It's not yet clear how long the first injection will last, though it worked for a year in rabbits.

"We expect [that time frame] to be similar in men, but that is just a minimum," Elaine Lissner, executive director of the Parsemus Foundation, told Cosmopolitan. "It seems to be pretty durable; we expect it to last for years. We just don't know how many yet."

In the United Kingdom, the future of male birth control may lie in the "clean sheets pill," a non-hormonal contraceptive that inhibits the release of semen altogether by contracting muscles and putting a clamp on the vas deferens, The Guardian reports. The pill has also been tested only in animals, and experts say we need more clinical studies on these products in the United States.

"We may be years away from viable new options for male birth control, but we are moving in that direction," said Dr. Jamin Brahmbhatt, co-director of The Personalized Urology & Robotics (PUR) Clinic at South Lake Hospital in Florida, who wrote about male contraceptives for Live Science.

"Most research is currently taking place in areas where birth control is more urgent due to population spikes, like China, India and Africa. The idea and the products will eventually find their way to the United States, provided they are alluring enough to investors and attractive enough to a large number of men," he said.