Male contraception: a new advance


Good news, guys: one day soon you may not have to worry about whether your girlfriend remembered to take her pill. The bad news? You might actually have to be the one who remembers to take it.

There are many options for female birth control, but only one for men (condoms). Could a more effective male birth control be available soon? Image via PlannedParenthood.org

A group of researchers at Baylor College of Medicine in Houston, the Dana-Farber Cancer Institute in Boston, and others have found a drug that may one day be used as a contraceptive in men. The drug, JQ1, blocks the tight packaging of DNA during sperm formation, which is critical for sperm to work normally. So far, the drug has only been tested in male mice, but it completely, and reversibly, blocks male fertility. The researchers reported no negative side effects from the drug. The results were reported in the August 17, 2012 issue of Cell.

The scientists decided to target the sperm DNA packaging protein BRDT for several reasons. First, it is only expressed in the testes, so destroying the function of this protein would not affect other tissues in the body. Second, by targeting BRDT, the drug would not alter testosterone levels in the body, which could have negative side-effects (like lower libido). Finally, other studies already found that deleting the BRDT gene from mice made them sterile, and men with mutations in the gene have abnormal sperm. This last one provided the rationale for studying the gene in mice first and trying to apply it to humans later.

Though the researchers saw no harmful side-effects, there were some side-effects. Well, really one: the male mice’s testes shrank while they were on the drug. While I’m sure your special lady won’t care, this might put some guys off the idea. The good news is that once the mice were taken off the drug, the testes soon returned to their normal size (and function).

There were a few other snags as well. For every mouse tested, there was some dose that provided complete contraception, but finding the right dose took some trial and error. Some mice were more resistant to the drug’s effects than others, but at the highest dose, all were sterile.

From mouse to man: the drug JQ1 works to block sperm production in male mice. With a lot more work from scientists (and a lot more money), a similar drug might be available to men in the future. Image via Wikipedia.

The other issue is how long it takes for the contraception to kick in. At least in mice, several weeks were needed to start seeing the effect. It might be a hard sell to get guys to take a pill for months before they can be sure that it will even work. The researchers state that they are optimistic that better drugs will be found that target the BRDT protein. So, if it ever hits the market, the drug may be more potent than JQ1.

So, what’s the point of all this anyway? Don’t we have perfectly good contraceptive options for women? (Well, as long as they remain legal anyway…)

The answer is yes and no. The options for women are very good, in that they do a very good job of preventing pregnancy. The problem is that they all come with varying levels of risk. The pill increases the chance of blood clots (and might lower a woman’s sex drive). Other side effects of hormonal contraceptives vary woman to woman, but can include bleeding between periods, nausea, and tenderness/pain in the breasts. The “ring“, a form of hormonal birth control, can also increase the chances of vaginal infection. The shot (Depo-Provera) also leads to loss of bone density.

Unfortunately, the side effects of the “aspirin between the knees” method proved to great for it to remain a viable alternative.

While all of these side effects are pretty rare (except the bone loss), they are risks that should be kept in mind. There are even serious side effects (which are very, very rare), but which include stroke and cancer. If an oral contraceptive could be developed in men, which doesn’t carry these side-effects, this would give couples more options to consider for family planning. This would especially benefit women who fall into high-risks groups and can’t normally use hormonal birth control.

Another benefit is that perhaps male birth control will be easier to get. Unfortunately, birth control has been under attack in the U.S. because of a perceived (but erroneous) connection to abortion. While I sincerely hope that the political attacks against female contraception will go away, and women can stop being vilified for wanting to plan when they have children, having an option available for men to use (besides condoms, which carry the same risk of pregnancy as perfect use of withdrawal) would be nice.

Related articles:

Reference
Matzuk MM, McKeown MR, Filippakopoulos P, Li Q, Ma L, Agno JE, Lemieux ME, Picaud S, Yu RN, Qi J, Knapp S, & Bradner JE (2012). Small-Molecule Inhibition of BRDT for Male Contraception. Cell, 150 (4), 673-684 PMID: 22901802

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