According to a recent article in The New York Times, male contraceptives are attracting growing interest from scientists, who believe they hold promise for being safe, effective, and, also important, reversible.
Scientists have been studying male contraception for many years, but so far no method has met the stringent safety and effectiveness criteria female methods do, writes Pam Belluck.
But some new approaches are encouraging enough that federal agencies are financing research. Some methods will be presented at an October conference by the Bill and Melinda Gates Foundation.
The most studied approach in the United States involves using testosterone and progestin to send the body signals to stop producing sperm, says Belluck. Evidently this is supposed to be safe and effective for most men, but there are questions about side effects.
So now scientists are investigating ways to interrupt sperm production, maturation, or mobility.
One potential pill, gamendazole, interrupts sperm maturation so that you’re making non-functional sperm.
Another drug blocks production of retinoic acid, which is important for sperm production. It involves the metabolism of Vitamin A. Vitamin A is converted into metabolically active retinoic acid, which binds to a protein in your cells called an RAR (retinoic acid receptor). The receptor protein initiates the expression of genes necessary for the creation of sperm. The drug being tested is an RAR antagonist (and there are concerns about side effects).
A neurobiologist at Harvard discovered that sperm tails contain calcium ion channels, with electrically-charged atoms “turbo-charging” the sperm to reach eggs. He’s working on a drug that would disable this channel.
Another experimental method involves injecting a copolymer gel into the scrotum to inactivate sperm. The injection is made into the vas deferens, the vessel through which sperm move before ejaculation. Within minutes, this gel coats the walls of the vas. Scientists believe this works by partially blocking the vas and also by rupturing the cell membranes of sperm, preventing them from penetrating ova.
Yet another method involves briefly heating the testes with ultrasound, which can halt sperm production for months.
Pharmaceutical companies haven’t signed on to any of these methods, waiting for something that’s shown to be both effective and relatively risk-free in healthy men.