Ultrasound as a new method of male contraception.

Twenty male cats were treated once or twice with 1 watt/sq cm of ultrasound for 10 minutes. Each of 24 male dogs received one to three treatments with 1 watt/sq cm for 10 minutes. Another six dogs were treated with 2 watts/sq cm for 15 minutes. Four Cebus apella monkeys were treated with the same dosage as that used for the cats and dogs. A dosage of 1 watt/sq cm for 10 minutes was also applied to four human patients without the use of anesthetics, and no pain or side effects were noted. In all treated animals as well as in human patients the results indicate that ultrasound significantly suppresses spermatogenesis according to the dosage and frequency of treatment, without any effect on Leydig cells or blood testosterone levels.