Research in Family Planning. Clyde V. Kiser ed. (1962) Princeton University Press. pp 346-347.

Control in the Male-
Direct Inhibition of Sperm Formation

  In attempting to uncover possible methods to be used by the male, practically all efforts have been focused on the process of sperm formation (spermatogenesis). The work can be divided into two categories - the suppression of pituitary gonadotropic hormones in order to cause, secondarily, the cessation of sperm production, and methods to inhibit the process directly by an attack on the testes. A seemingly drastic attack, but nevertheless of considerable interest, has been the study of heat influence on the testes. In 1954, a Swiss physician claimed that heat could be applied to the testes to achieve contraception through temporary male sterilization.23 In her words, "the treatment consists of a sitting bath of 45 minutes, at a temperature of 116 F. daily, for a period of 3 weeks. This treatment results in sterility which lasts for at least 6 months. After that time, normal fertility returns. Where sterility of longer duration is desired, the treatment must be repeated every 6 months." She continues that "the cheapness of the method is guaranteed by the fact that the only cost to the individual is that of a bucket of hot water" and that in many countries, for the poor, "squatting is a favorite mode of relaxation." In the report it is claimed that the method has been used successfully on nine volunteer subjects over a ten year period. Further, it is claimed that the method was put in practice in India between 1930 and 1950 and that it enjoyed remarkably good acceptance and gave the desired effect. This may sound fantastic, and in view of the fact that the report quoted contains no substantiating scientific evidence, one might be inclined to discount it summarily. However, recent investigations carried out on a scientifically controlled basis indicate that the heat treatment described would cause temporary male sterilization as claimed. In studies on men in the United States and Japan, the effect of heat on sperm production has been demonstrated very clearly.24 If the testes are exposed daily for three days to a temperature of 45 C. for about fifteen minutes, the sperm count falls to very low levels and does not return to normal for about fifty days. If exposure is made at intervals of about two weeks, the sperm count can be held at low levels.

23Voegeli, Martha: "Contraception Through Temporary Male Sterilization." Chalet Marlefried, Goldiwil-ob-Thun, Switzerland, 1954.

24Tokuyama, I.: "Effect of heat on Spermatogenesis," Personal Communication, 1960.