 Orthodox rabbis believe that the positive commandment of being fruitful and multiplying is a male obligation.Consequently, wives may choose abstinence as birth control, but husbands are not permitted to decline their wives if they are not in niddah.Contraceptive measures that lead to male sterility, are not ever permitted for their interfering with a man's obligation, only ever being permitted in life-threatening circumstances for the man such as some forms of cancer.