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Table 3 Effects of increase in scrotal temperature through scrotal insulation on total sperm count in men

From: Hormonal, chemical and thermal inhibition of spermatogenesis: contribution of French teams to international data with the aim of developing male contraception in France

Authors Heating Nb a Effect on sperm number
Method Daily duration Frequency During heating After heating
w b
value c
value d
Robinson & Rock 1967 [90] Insulating (oilcloth) underwear
SAT e +0.8 °C
Daytime Every day for 6 to 10 weeks 10 w 3–9
w 10
w 1–3
w 10
w 11
w 12–14
Wang et al. 1997 [91] Athletic supports with either 1 or 2 layers of P f, or 1 P layer plus 1 Al g –impregnated P layer
SAT +0.8–1 °C
>20 h Every day for 24 to 52 weeks 21 No effect whatever the number or type of layers
  1. Legend: a number of men; b weeks; c mean value of total sperm number/initial total sperm number (%); d maximal value of total sperm number/initial total sperm number (%); e SAT scrotal achieved temperature; f polyester; g aluminum