Phyllis Leppert, Professor Emerita at Duke University and President of the Campion Fund, explores the biological complexity of sex differentiation. While traditionally viewed as a strict male-female binary, scientific research reveals that sex exists along a spectrum. Leopard explains how genetic, hormonal, and molecular processes contribute to the diversity of human bodies. She challenges common misconceptions, illustrating how biological variation is the norm rather than the exception. This video is part of an educational initiative to promote discussion and further understanding of human development.