"The future of male contraception"

The media has reported that a Male Birth Control Pill may be available by 2005. Work on the Male Pill has been in progress for forty years, but to say that it will be available for general use at any time soon is both optimistic and misleading. Spermatogenesis, a 72 day process, is directed by pituitary FSH (Follicle Stimulating Hormone). Administration of testosterone shuts down FHS production, but doses sufficient to do this cause side effects. The addition of a progesterone allows for the inhibitory effect at lower testosterone doses and seems to be well tolerated. Currently, effectiveness is only 90-95% which is not reliable enough for most couples. Safety is another issue. The potential side effects of testosterone, primarily to lipids, prostate and to sexual function, that need to be delineated. Also, the longterm effects of progesterone on men are not known.

In the realm of contraceptive vaccines, the man's (or perhaps the woman's) immune system is targeted to destroy or impair sperm. The sperm contains the haploid chromosomes which are genetically different than that man's own genome. This would trigger an immune response were it not for the "Blood-Testis Barrier" that shield the sperm. Other approaches are also under investigation. Sperm do not become motile, or achieve the ability to fertilize until they leave the testis and pass through the epididymis, a six metre long network of canals which then form the vas deferens. Nobody yet understands how this maturation process occurs, but various drugs are being developed to impair these processes. Triptolide, derived from a Chinese herb is one such product under study.

Finally, fertilization depends on the sperm's ability to dissolve the outer layer of the female's ovum, and fuse to it, end empty its genetic package therein. This involves a complicated reaction between the sperm's plasma membrane and the acrosome, a small bag of enzymes near the tip of the sperm. This reaction apparently requires the activation of a calcium dependent channel, and the calcium channel blocker, nefedipine, has been shown to inhibit this in vitro.

Despite these promising avenues of research, there are many cultural, societal and interpersonal issues with male contraception. It is generally accepted that marketing these products to men may be difficult, as is the task of marketing most health products to men. Many men do not have a regular relationship with a GP or a urologist the way women do with their gynecologist or FP.

His compliance with daily medications could certainly become an issue for many couples. Women would have to trust a partner, who doesn't risk pregnancy, to take it. Some companies are considering the marketing of a test kit to assess the male's sperm levels as proof of his compliance. This could certainly put a damper on trust, spontaneity and intimacy.

In terms of an improved vasectomy, various attempts to block the vas reversibly, with materials such as Krazy Glue, and others, are also under investigation. Some are promising, but none so far have the success rates (greater than 99%) that I would consider acceptable. Contrary to popular misconception, laser vasectomies are not in general use anywhere that I know of. I promise I will let you all know as soon as it is.