While women have had more birth control options than their counterparts, researchers have been trying to change this. There are on-going attempts to develop everything from a pill to a gel which men could use in the future. 

Now, in a new study, scientists from China have drawn inspiration from an unexpected source to develop what could potentially become a reversible male contraceptive — layered cocktails. Specifically, the Galaxy cocktail, a colorful drink which is characterized by the formation of distinct layers. But when stirred or heated, the layers in the glass blend into a uniform liquid.

Led by Xiaolei Wang, the team of researchers from Nanchang University, wanted to see if they could make similar use of liquid layers to design a reversible form of contraception. So how exactly did it work?

First, to quickly refresh our knowledge of male reproductive anatomy — you might know the vas deferens, the duct which transports sperm from the testicle to the urethra. The new method of birth control essentially involves injecting four layers of liquid materials to block this duct.

And what are these materials exactly? A hydrogel to effectively block the sperm, a chemical known as EDTA which helps kill the sperm, and two layers of gold nanoparticles. Just like the beverage that inspired the method, the contraception can be reversed by using a near-infrared lamp to dissolve the layers. To test it out, the researchers performed an experiment by injecting the vas deferens of male rats.

It was found to be successful in preventing them from impregnating female rats for over 60 days. The research team was also able to restore fertility in the rats by using the easy, aforementioned method of near-infrared irradiation.

Speaking to IFLScience, Dr. Wang explained how one could potentially control how long they want the contraceptive period to last by varying the injection dose. He also noted that the quality of sexual life would not be impacted during the entire contraceptive period.

While all these benefits sound highly promising, it should be noted this is still in the early stages of development. The efficacy needs to be tested in other species in addition to observing whether the user suffers any short-term or long-term harm after being injected. Clearly, it will be a long time before this can be tested on humans. 

"For adult males with a fixed sexual life, it is more convenient, reasonable, and humanized to provide a medium to long-term contraception method with flexible reversibility," the scientists wrote in the study. "With the development of men’s ideas, consciousness, knowledge, and attitude, we believe that more and more men will feel obliged to shoulder the burden or pregnancy, both for fairness and risk aversion, which is also the best way to care and love their wives."