One of the first non-hormonal male birth control breakthroughs came from researchers at the University of Massachusetts in 2005 [source: Smith]. Rather than shutting down sperm production via testosterone, the medical school scientists sought to disable sperm instead. When sperm form in the testes, their tails are extant but immobile. Not until the sperm pass through the epididymis (the long, coiled tube that connects the testis to the vas deferens) are they able to swim. The University of Massachusetts team hypothesized that blocking the Cs protein, which "turns on" the sperm's tails on their journey through the epididymis, could permanently incapacitate sperm.
The Cs protein concept wasn’t the only non-hormonal idea floating around the medical community at the time. Researchers around the world were working on other non-hormonal male birth control projects, based off of ideas such as turning off a protein that triggers sperm maturation, and research into a cancer medication, lonidamine, which inadvertently terminates sperm production. Despite promising lab testing, the FDA has yet to green light either.
In 2011, non-hormonal male birth control made the rounds in science news headlines again. Columbia University genetics professor Debra Wolgemuth ran across a compound, BMS-189453, technically classified as a “testicular toxin,” that rendered male mice infertile without affecting their testosterone levels or sex drive [source: Rochman]. The compound prevents the body from breaking down vitamin A, which provides a key protein for regulating sperm production. Specifically, it inhibits the metabolism of vitamin A into retinoic acid that then forms a protein linked to spermatogenesis. Wolgemuth and her team determined that a similar vitamin A-blocking compound derived for men could act as a reversible, non-hormonal birth control. On the down side, the method also has raised red flags for some in the medical community, who worry that messing with the body’s vitamin A uptake could result in immune system deficiencies and other negative side effects [source: Perry].
Around the same time that BMS-189453 snagged media attention, another non-hormonal male birth control treatment with a similarly unwieldy name also awaited at the pharmaceutical gates.