Effective communication between clinicians and parents of young children with developmental delays can decrease parents' anxiety, help them handle bad news, and improve their adherence to proposed interventions. However, parents have reported dissatisfaction regarding their current communication with clinicians, and they face cognitive and emotional challenges when discussing their child's developmental delays. In this paper, we present visualization as a facilitator of parent-clinician communication and how it could address existing communication challenges. Parents and clinicians anticipated visualization webtools would aid their communication by helping parents gain a better understanding of their child, acting as objective evidence, and highlighting the strength of the child as well as important medical concepts. In addition, visualization can act as a longitudinal record, helping parents track, explore, and share their child's developmental progress. Finally, we propose visualization as a tool to guide parents in their transition from feeling emotional and disempowered to advocating with confidence.