In the past, responsibility for contraception has fallen primarily on women. Although women have many options, each form of birth control varies in how convenient and effective it is, and how it affects a woman's health.
Today, many men also want to control their own fertility and take an active role in preventing unplanned pregnancies. Despite advances in female contraception, abortion and teen pregnancy rates are still high, and about half of all pregnancies worldwide are unwanted or unplanned. Male contraception options can significantly influence birth rates in developing countries. Fortunately, many researchers are developing new methods for male contraception.
Currently, there are three birth control options for men: withdrawal, which has a 27 percent failure rate; vasectomy, which is permanent; and condoms, which can fail and produce pregnancy rates as high as 15 percent.
On the horizon
There are general three approaches to new contraceptive development.
1. Hormonal methods, which, like the birth control pill for women, can have unintended consequences
2. Non-hormonal but systematic methods that affect the whole body
3. Non-systemic methods, which specifically target sperm
All approaches work by somehow inhibiting sperm production, motility or its interaction with a woman's eggs. Most of the development and progress in male birth control is in the third category.
Non-systemic methods in development
Vas-based. The vas deferens is a tube that passes sperm from the testes, where it's produced, to the penis. Unlike a vasectomy, which permanently severs the vas deferens, vas-based contraception methods are temporary. For example, a procedure called RISUG, Reversible Inhibition of Sperm Under Guidance, uses a polymer inserted into the vas to kill sperm. When a man no longer has a need for birth control, his physician flushes the polymer out of his system. Scientists have had good results in clinical trials with RISUG.
Other vas-based methods include implants, plugs and injections that provide a barrier to, or kill, sperm.
Heat-based. Heat affects fertility in men. Researchers have developed ways to use heat to temporarily render a man infertile. For example, ultrasound is simple, convenient and temporary, and is the most promising heat-based forms of birth control. In other studies, heating the testes with water rendered men infertile for six months. After six months, men can let their fertility gradually return or repeat the heat procedure to continue contraception.
Oral. Chinese herbs and blood pressure medications are just two of the non-hormonal, oral methods scientists are evaluating.
While we're still probably a decade away from having reliable male birth control, scientists are making significant advances in developing safe and reliable forms of male contraception.
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