Descriptions of and rationales for the division of responsibility for elderly parents by 50 sister-brother dyads in sibling groups that included only one sister were analyzed qualitatively to explore why provision of services is a gendered activity or at the very least appears to be. Three interrelated factors were identified: (a) Family members adopted cultural assumptions about what constituted gender-appropriate behavior; (b) the lone sister typically was "in charge" of service provision; (c) brothers' actual contributions tended to be considered unimportant by both sisters and brothers. The gender composition of the sibling group is suggested to be an important context within which the meanings of gender and parent care are negotiated.