Sex abuse of minor children by Catholic priests has been a persistent and widespread problem in the Church in recent years. Although over 8 in 10 of victims have been boys, the idea that the abuse is related to homosexual men in the priesthood has not been widely accepted by Church leaders. The influential report of the John Jay College of Criminal Justice on the causes and context of Catholic clergy sex abuse (hereafter “JJR2”, for John Jay Report 2) concluded that widespread American abuse was not related to the share of homosexual priests because the reported increase in “homosexual men in the seminaries in the 1980s …does not correspond to an increase in the number of boys who were abused.” To test JJR2’s conclusion, I examined the available data on clergy sexual orientation and the incidence of clergy sex abuse. The share of homosexual American priests over time was estimated from a 2002 survey by the Los Angeles Times newspaper that included questions about sexual orientation, age and year of ordination. Abuse was measured by reports from Catholic dioceses, the same data used in JJR2. I looked only at allegations of current abuse, and statistically adjusted the findings to eliminate differences due to the age of abuser and year of abuse. My findings showed that the increase or decrease in the percent of male victims was almost perfectly associated (the standardized regression coefficient was .98) with the increase or decrease of homosexual men in the priesthood. Among victims under age 8, the standardized coefficient was lower but still strong (.77). This indicates that 1) the abuse of boys is very strongly related to the share of homosexual men in the priesthood, but that 2) easier access to males among older victims (ages 8-17) may have also been an enabling factor. The increase or decrease of overall abuse was also highly associated (.93) with the increase/decrease of homosexual priests; not surprisingly since such a high proportion of victims were male. This finding was robust; the unadjusted correlation was still a strong .90. About half of this association was accounted for by the rise of subcultures or cliques of sexually active homosexual priests and faculty in Catholic seminaries. Prior to the 1950s the proportion of homosexual men in the priesthood was about the same as in the general population. By the 1980s homosexual men made up over 16% of the presbyterate, which is over 8 times that of the general population. That increased presence of homosexual priests has been accompanied by an increase of about 24 additional incidents of currently-reported abuse per year. Extrapolating to all reported abuse results in an estimate that if the concentration of homosexual men in the Catholic priesthood had remained at its relatively low level of the early 1950s, abuse would have been about 85% lower, sparing an estimated 12,594 children, mostly boys, from sexual victimization by Catholic priests in the United States.