Like embryonic stem cells, the cells on a newborn’s foreskin are full of potential: Scientists can use the growth factor within to grow all kinds of skin, helping make grafts for burns, ulcers, and open wounds. In fact, a single foreskin donated by a hospital can help make 250,000 square feet of new skin tissue, generating millions in profit for labs and cosmetic companies. The “neonatal fibroblasts” are an especially hot commodity in cosmetics, producing collagen for injectable “rejuvenation” products and skin creams.