<p>This study incorporated a developmental framework, examining safety discussions between different age youth (pre-adolescent, adolescent) and their parents, and considered if these differ for mothers versus fathers or for sons versus daughters. Twenty pre-adolescents (11- and 12-year-olds) and twenty adolescents (15- and 16-year-olds) and their parents participated in interviews and negotiation tasks to explore: (1) what physical safety issues children and their parents disagree about most often; (2) how mothers and fathers negotiate with one another about safety issues related to their child; and (3) how parents and their child negotiate about safety issues. Results from conventional content analysis revealed that developmental stage, child sex, and parent sex each affected the findings. With increasing age, there were notable differences in the types of safety disagreements between children and their parents. Additionally, sons disputed their likelihood of injury and potential severity of injury in discussions with their parents, more so than daughters. Fathers were more tolerant of children engaging in risk behaviors and showed more openness to negotiation about risk behaviors in comparison to mothers. Fathers often viewed their children experiencing minor injuries as valuable learning experiences, whereas mothers did not. This research provides a starting point for understanding how safety issues are negotiated within families and the factors that affect these. Implications for injury prevention are discussed.</p>