Using a sample of 982 mothers who reported on child care and living arrangements involving uncles, and case records documenting the sexual abuse of 171 children by 148 uncles, this study examined the ways uncles ordinarily become involved with children, the conditions under which that involvement becomes associated with sexual abuse, and the role gender plays in this dysfunction. Among the findings, it was noted that although aunts were responsible for 28 times more child care than uncles, uncles were responsible for 48 times more child sexual abuse. Although female children do not have more exposure to uncles than do males, they appeared four times more likely to be victimized. About 19% of the abusive uncles lived with the children they abused, and most of the remainder came into contact with them as child care providers or during overnight visits. Implications for practice are discussed.