The most advanced progress in male contraception is on the hormonal front, Dr. Brian Nguyen, an Ob-Gyn and assistant professor with the Keck School of Medicine at the University of Southern California, tells The Times.

He is on a team conducting clinical trials with the Center for Male Contraceptive Research and Development, an international network of professionals supporting advances in male contraception. It is sponsored by the Eunice Kennedy Shriver National Institute of Child Health and Human Development.

They are actively recruiting for volunteers in Torrance in Los Angeles County, as well as in Sacramento. The study involves a hormonal drug that suppresses all the signaling for sperm development.

But the quest for birth control to be used by sperm-producing partners means so much more than giving people options; it’s about equality for everyone, experts say. They argue that discussions tend to portray reproductive rights as a women’s rights issue. While that is true, both men and women benefit from expanded reproductive autonomy.

“We’re only really giving half of the population the tools they need to prevent an unintended pregnancy,” Heather Vahdat, the executive director of the Male Contraceptive Initiative, tells The Times.

One of the most promising ongoing trials conducted by Nguyen’s team at the Lundquist Institute in Torrance involves a gel that men can apply to their shoulders. The hormonal gel combines both a progestin and testosterone, which together block the body’s signals for producing its own testosterone and sperm, he explains. The testosterone in the gel replaces the body’s own testosterone, preventing negative effects on libido, sexual function, muscle mass, and energy….

….you don’t have to get a sperm count to zero to make a person infertile. A count of 10 million to 20 million greatly reduces the likelihood of pregnancy.

“Your normal semen contains about 40 million to 300 million sperm per milliliter, which is huge, right? And if you ask yourself, why evolutionarily does a man need that much sperm per milliliter of semen in order to impregnate women? That’s because you need that many. The process of getting that sperm and egg is extremely perilous,” Nguyen says. “So even at 10 [million] to 20 million, you’re expecting this man is going to have difficulty achieving a pregnancy….”

The above comes from a Dec. 21 article in the L.A. Times.