Eoin Whelan, PhD and Ralph Brinster, VMD, PhD, along with a team of researchers at Penn’s School of Veterinary Medicine and Children’s Hospital of Philadelphia are featured in Penn Today for their recently published study in Stem Cell Reports. In the paper, they identify roadmap of how the complex development of male germ cell differentiation is achieved through gene expression and epigenetic changes. This exciting research lays the groundwork to help childhood cancer survivors become parents later in their lives.