Adult stem cell

Adult stem cells are undifferentiated, found throughout the body after embryos/fetal development, that multiply by cell division to replenish dying cells and regenerate damaged tissues. Professor Farnsworth used adult stem cells in his birthing machine to ressurect the Planet Express crew, LaBarbara, Zapp, and Kif.

Controversy
Unlike embryonic stem cells, the use of adult stem cells in research and therapy is not considered to be controversial as they are derived from adult tissue samples rather than destroyed Human embryos/fetal. They have mainly been studied in Humans and model organisms such as mice and rats. However, this is a fact which Fry disagrees with.