Scientists from the University of Giessen in Germany, reporting in the New Scientist, have warned that heated car seats could damage sperm production.The optimal temperature for healthy sperm production is between 35 and 36 degrees centigrade , which is 1 to 2 degrees centigrade lower than core body temperature. However, having tested the effects of heated car seats on 30 healthy men, scientists found that the average scrotal temperature was 37.3 degrees centigrade . This was enough of an increase to damage sperm production, according to Andreas Jung, leader of the study.
The study involved 30 healthy volunteers, who sat on heated car seats for 90 minutes while fitted with temperature sensors. An hour into the trial, the average scrotal temperature of the men sitting on the heated car seats was 37.3 degrees centigrade, with one man reaching a high of 39.7 degrees centigrade . In contrast, the average scrotal temperature of volunteers sitting on non-heated car seats was 36.7 degrees centigrade . If the scrotum is subject to higher than optimal temperatures, effects
also attributed to laptop use and keeping a mobile phone in a trouser pocket, the body's ability to keep the testes cool is compromised and sperm are able to swim less far. This has a negative impact on men's fertility, with studies also suggesting that the partners of men who drive for over three hours a day take longer to conceive. Tight-fitting underpants have also been found to reduce sperm counts, as compared to men wearing loose-fitting underpants, a Dutch study has found.