Male contraception: Prospects for sound and ultrasound

The worldwide human population growth rate, which doubled during the 20th century, as well as the increasing fertility rate, have contributed to an increasing and evolving emphasis on contraception. With respect to female contraceptive methods, many have been developed, marketed, and are widely available. In contrast, male contraception has been limited to condoms, which pose logistical challenges, and vasectomy, which is largely irreversible. The use of sound to achieve effective and safe male contraception is a promising but unproven hypothesis. Based on the existing and incomplete totality of evidence, we hypothesize that the combination of sound with a modified ultrasonic technique in a single system will provide a practical delivery method that merges all of the appropriate and prescribed frequencies to have spermicidal qualities that may result in effective and safe male contraception. It is also plausible that any experimental male contraceptive method that heats the testicles where they can no longer produce sperm offers the possibility of a favourable benefit to risk ratio. The single system combining sound with a modified ultrasonic technique includes an acoustically suitable pad to assure proper transmission and delivery without concern for injury from the ultrasound frequencies, an amplification and regulation module, a frequency source generator, the complementary heat created along with external and targeted directionality, and various transport methods, such as wired, wireless, or remote. This methodology also offers the ability to move quickly to prototype, achieve multiple patent crossovers, secure and employ commercially available technologies, and provide the opportunity for rapid regulatory approval worldwide. These concepts have been explored in basic research in many animal species as well as humans. To achieve an adequate totality of evidence, the test of this hypothesis requires further basic research in humans to clarify the relevant mechanisms, clinical and observational epidemiologic studies to further explore the hypothesis, and large-scale randomized trials to detect the most plausible magnitude of benefits of this promising but unproven technology. It is plausible that this technology will represent a major breakthrough to combat world population growth. It is also plausible, that, to paraphrase Thomas Huxley, this beautiful hypothesis will be slain by ugly facts.