In this letter to the editor, the authors question whether the standard argument for the apparent gender bias in suicide rates among 15-24-year-olds is satisfactory. It is usually argued that young females have a higher frequency of attempted suicide than do young males. The widespread use of marijuana corresponds with the increases in completed male suicide & attempted female suicide. One of the lesser known effects of marijuana is to increase levels of interferon-gamma, a factor which can seriously compromise normal neurophysiology. When interferon-gama is elevated, it causes a marked serotonin deficiency which is symptomatic of major depression & suicide. Females can augment serotonin from ovarian estrogen, a biological option unavailable to males. The authors believe this accounts for the gender bias in youth suicide & that the widespread use of marijuana in Western society is the principal reason for the increase in suicide among young males. Reductions in estrogen can also occur in response to chronic stress. (12 refs.)