Two years ago, San Francisco-based Parsemus Foundation introduced an incredible new birth control option for men which works like a vasectomy but is actually reversible.

Known as Vasalgel, the contraceptive is a gel injected into the vas deferens. It can be flushed out with another injection months after the first dose, and actually requires no use of condom.

At that time, Vasalgel had successful results in rabbit and baboon studies. Developers expected to perform human clinical trials by 2015.

Another Birth Control Option For Men

There are a host of contraceptives on the market for women. For men, the most reliable options are still vasectomy and the use of condoms. The former, in particular, is not a popular choice.

What's more, there are still 85 million unintended pregnancies every year, so experts believe there is still room for improvement.

Fortunately, Vasalgel has passed a major hurdle that could push its development further. New rabbit trials revealed that one injection of Vasalgel can offer effective and safe contraception to males after at least 12 months.

Study leader Donald Waller said Vasalgel can produce a very rapid contraceptive effect, which lasted throughout the trials because of its hydrogel properties.

"These features are important considerations for a contraceptive product to be used in humans," said Waller.

Waller and his colleagues gave 12 male rabbits a single injection of Vasalgel in different doses. Afterwards, they found that eleven of the animals were "azoospermic" or had no traces of sperm during ejaculation. The other had only small amounts detected before becoming azoospermic as well.

Throughout the 12-month trial, the 12 male rabbits were unable to impregnate female rabbits. Researchers also did not find any abnormal responses from the rabbits.

Seven of the animals had the Vasalgel flushed from their vas deferens. Their sperm quickly went back to normal.

The results confirm that Vasalgel is fully reversible, but instead of 2015, human trials for the condom-less contraceptive will begin later this year. Parsemus says Vasalgel could be available to the public in early 2018. The foundation's goal is to make the contraceptive affordable enough to all men across the world.

The findings of the study are reported in the journal Basic and Clinical Andrology.