that the various forms of cancer can be categorized as pubertal and gerontological. Anthropological research is currently being conducted on cancer as a natural evolutionary process through which natural selection destroys environmentally inferior phenotypes while supporting others. According to this theory, cancer comes in two separate types: from birth to the end of puberty (approximately age 20) teleologically inclined toward supportive group dynamics, and from mid-life to death (approximately age 40+) teleologically inclined away from overpopulated group dynamics. See also Cancer cell Armitage–Doll multistage model of carcinogenesis Linear no-threshold model Oncogenic retroviridae protein References Further reading Radiation health effects