Based on youth participatory action research with Colombian street girls, I illustrate discrepancies between human subjects protection guidelines and practice in youth research, providing guidance for operationalizing federal Office of Human Research Protection regulations in geographic research. I problematize taken-for-granted human subjects definitions including childhood, vulnerability, protection, and consent, all of which rely on context-specific assumptions that do not hold across all places and circumstances. Through the enactment of a care ethics practice in fieldwork, I suggest that geographers can move toward more truly critical research praxis by making socially responsible action in the field the driving force of "subject" protection.