Stefania Nicoli, PhD. Photo courtesy Yale School of Medicine The outer surface of the skin, noted for its regenerative processes, may owe its resilience to lessons learned before birth. In a study published October 10 in Nature Communications , researchers at Yale School of Medicine report that embryonic skin stem cells establish the physical and molecular groundwork that allows the body to repair itself throughout life. Led by Kaelyn Sumigray, PhD, and Stefania Nicoli, PhD,