Lead researcher Sabatino Ventura explains, "The sperm is effectively there, but the muscle is just not receiving the chemical message to move it." Unlike hormonal versions of a male pill, this one would not affect hormones. In previous tests on mice, researchers found that hormone-based drugs were irreversible in some cases and caused birth defects in those who could procreate after the treatment. The only negative side effect of the protein-based pill that researchers could measure was a slight decrease in blood pressure of the mice tested. Researchers admit the blood pressure drop may be problematic in humans, but it's definitely a start in the process to find a safe, effective method for men when it comes to oral contraceptives.

Other options being tested include a gel that combines testosterone and nestorone (a horomone like progestin) and is applied to men's arms. It's reversible, and side effects seem few, plus its efficacy is comparable to women's oral contraceptives. Researchers hope testing will be complete by the end of 2016, according to WebMD. 

Vasalgel is another option being tested, only this gel is injected into the vas deferens and can last for years. It is flushed out when the man no longer wishes to prevent contraception; however, the process needs fine-tuning, according to researchers. But once it is cleared for human testing, researchers say men are interested -- there's even a 31,000-person waiting list, proving men are ready to have more contraceptive options.