How close are we in achieving safe, affordable and reversible male contraceptives?

The world population, currently estimated to be over six billions, is expected to double in the next forty years. The projected growth will cause severe over crowding that will have an adverse effect on the ecological health of the planet. A recent survey by the United Nations found that a majority of men in many countries are willing to participate in family planning by taking full control of their fertility. However, the available contraceptives for men have either higher failure rates or they are irreversible. Thus, the contraceptive needs of tens of millions of men go unmet every day resulting in millions of unwanted pregnancies, and hundreds of thousands of abortions. Since the introduction of oral contraceptive (pill) for women over five decades ago, there have been numerous collaborative efforts by scientists and pharmaceutical companies to improve the effectiveness and delivery of contraceptives to women who wish to safely regulate their reproductive physiology. However, the contraceptive options available to men have not changed in several decades and are still limited to the use of condoms and timely withdrawal (coitus interruptus) or under going a minor surgical procedure (vasectomy) that prevents the release of spermatozoa during ejaculation. The first two methods have relatively higher typical-use failure rates, whereas the last approach is largely irreversible and not suitable for younger men. Despite non-stop efforts worldwide, we may still be several years away from providing safe, effective and affordable male contraceptives which will allow both men and women to participate fully in family planning. In this article, we will discuss various contraceptives currently available to regulate male fertility. In addition, we will summarize potentially new contraceptives for men that are at various stages of research and development. Finally, our intention is to discuss details of two safe, reversible and affordable male contraceptive approaches that are inching closure to being approved for use by the masses in India and China, the world's two most populous nations.