Foreskin fibroblasts are big business. A fibroblast is a piece of human skin that is used as a culture to grow other skin or cells -- like human yogurt kits. Human foreskin fibroblast is used in all kinds of medical procedures from growing skin for burn victims and for eyelid replacement, to growing skin for those with diabetic ulcers (who need replacement skin to cover ulcers that won't heal), to making creams and collagens in the cosmetics industry (yes, the product that is injected into puffy movie-starlet lips).