Sexual intercourse with withdrawal just before ejaculation; coitus interruptus.The term derives from the Bible (Genesis 38:9): “And Onan knew that the seed should not be his; and it came to pass, when he went in unto his brother’s wife, that he spilled it on the ground, lest that he should give seed to his brother.” Due to a misinterpretation of this passage, onanism is often incorrectly used as a synonym for masturbation.Coitus interruptus is sometimes used for purposes of contraception, though it may fail because the preorgastic secretion contains spermatozoa in 25 per cent of males. As to the psychological effects, there is considerable disagreement. Lowen (1961) states: “Any attempt to control or restrain the mounting genital excitation at this time is unpleasant and may be painful. Such a procedure frequently results in a shock to the body.” Lehfeldt (1961) believes it may have other effects: “. . . it is certain that the method often produces psychological disturbances such as lack of female orgasm or male impotence, which may lead to marital maladjustment. Switching to a different contraceptive technique usually cures these ills.” As to lasting psychological harm, Gutheil (1959) has this to say: “Early psychiatrists (including Freud) believed that coitus interruptus—like masturbation—was harmful, and that it led to a so-called ‘actual neurosis.’ Today, this concept is no longer considered valid.”