Theory explains why 25 percent of cultures cut male genitals
http://www.physorg.com/news124120381.html
03/07/2008
"Almost 25 percent of indigenous societies practice some form of male genital cutting, ranging from circumcision to the ritual removal of a testicle. The reason, reports a Cornell scientist, may be to reduce pregnancies from extramarital sex. More subtly, it could be to reduce conflict among men."