Quote Originally Posted by War Angel
Because according to the Judaism, and therefore Christianity and Islam, wasting sperm is prohibited. That's why sodomy and fellatio (to the point of ejaculation, anyway) are prohibited as well.
Wasting? But it generates again afterwards, so it's not like wanking will prevent you from having children. Oh, well, those are ancient rules, so it was a different culture, and I guess it's hard to understand it in today's mentality.