 |
IN FOCUS: ARTICLE |
|
|
|
 |
|
|
Is There a Birth Control Pill for Guys?
by Christy Brownlee, 11.22.05
It's much easier to control a single egg than millions of sperm. |
|
"When is there going to be a birth control pill for men?" It's a question many women have asked when faced with all the birth control choices that make pregnancy prevention their responsibility. And many men want to know when they will have more options for taking the lead on pregnancy prevention.
The good news is researchers are making strides in creating promising new male contraceptives — a move that will give both women and men more flexibility in preventing pregnancy.
One Egg, Millions of Sperm
Every pregnancy needs a sperm and an egg. Women have many options for preventing pregnancy — including the pill, patch, ring, diaphragm, sponge, and others. The only birth control methods that depend on men are abstinence, condoms, withdrawal, and vasectomy — and vasectomy and withdrawal are not recommended for teen guys.
So why do women have so many more options? According to Dr. Narender Kumar of the Population Council, most methods of birth control are designed for women because of biological reasons. "Females release one egg per menstrual cycle, but males make millions and millions of sperm a day," he says. It's much easier to control a single egg than millions of sperm.
But even though it's easier to make birth control methods for women, studies show that an increasing number of men want to take an active role in preventing pregnancy.
Researchers hope to find a method of birth control for men that's similar to hormonal contraception for women. Hormonal methods like the pill, ring, patch, and shot, are 99.7 percent effective against pregnancy when used correctly, and are easily reversible.
In the Works
At the University of Washington's Male Contraception Research Center, Dr. John Amory, assistant professor of internal medicine, and other scientists are working to develop a hormonal method of birth control for men. The most promising research, he says, focuses on using shots of testosterone to turn off sperm production.
Normally, testosterone is produced in the testicles, leading to sperm production. But if testosterone is injected directly into the bloodstream, it sends signals to the pituitary gland saying that the level of testosterone is too high. The pituitary gland then signals the testicles to slow down testosterone production, which in turn, turns off sperm production.
Armory and other researchers have found that this mechanism decreases sperm production in about two-thirds of men, with few side effects. But in order for testosterone shots to be used as a reliable form of contraception, the shots will need to be more effective in lowering sperm production. Researchers believe that adding the hormone progesterone to the shots might make them more effective.
Pills and Vaccines
Scientists theorize that putting testosterone and progesterone into a shot, a patch, or an implant could also work to lower sperm counts. But since digestion breaks down testosterone, putting hormones into a pill wouldn't work. That's why some researchers are trying to find other methods that would lower sperm counts or make sperm unable to fertilize an egg.
One possibility is to immunize men against the proteins that are needed for sperm to fertilize an egg. Scientists at the University of Washington tested this method in monkeys and found that it caused most of the monkeys in their study to become infertile. When the scientists stopped giving the shots, most monkeys became fertile again. But since some monkeys remained infertile even after the shots were stopped, scientists have to do more work before they try a similar method on humans.
Condoms Are Here to Stay
Amory says he expects the first male birth control drugs based on the testosterone/progesterone mixture to be available in about five years. However, he notes, male birth control — like hormonal birth control for women — won't offer any protection against sexually transmitted infections. Only latex and female condoms reduce the risk of both pregnancy and infection. So condoms remain the best choice for sexually active people who have more than one partner — or whose partners have more than one partner. |
|
|
|
Printable Version
Email this page