outside the body for cooling because they operate for sperm production at a slightly lower temperature than the rest of the body, and boxer shorts allow the testicles to operate within the required temperature range. The compression of the genitals in boxer briefs, briefs, thongs, etc. may cause the temperature to rise and sperm production to fall. There is a similar theory regarding testicular cancer risk. Other sources dispute this theory. A study in the October 1998 Journal of Urology, for example, concluded that underwear type is unlikely to have a significant effect on male fertility. Image gallery References External links 1990s fashion Undergarments Men's culture