This article analyses data from a longitudinal, ethnographic study conducted in the United States to examine how 100 mothers of children with genetic disorders used the Internet to interpret, produce, and circulate genetic knowledge pertaining to their child's condition. We describe how they came to value their own experiential knowledge, helped shift the boundaries of what counts as authoritative knowledge, and assumed the role of genetic citizen, fighting for specific rights while shouldering and contesting concomitant duties and obligations. This exploration of e-health use contributes to our understanding of the social practices and power relations that cut across online and off-line worlds to co-produce genetic knowledge and genetic citizenship in multiple contexts.