Dr. Hossein Gharib was born in Tehran, Iran on February 2, 1940. His father was Dr. Mohammad Gharib (1909–1975), a former Professor and Chair of Pediatrics at Tehran University (1938–1975), generally regarded as the "Father of Pediatrics" in Iran. In 1998, Hossein Gharib edited and published a book in Persian about his father which includes a collection of essays from his father's family, patients, friends, and colleagues. The second edition is scheduled for publication in late 2011. For his lifetime of service, Dr. Mohammad Gharib was honored on a stamp issued by the government of Iran in 1991. Hossein's mother was Zahra Gharib (1915–2010), daughter of Ostad Abdolazim Gharib (1877–1965), a renowned professor of Persian literature and the first person to develop a modern grammar for the Iranian language. Ostad Abdolazim Gharib was recognized for his major contributions to Iranian literature by a stamp issued by Iran in 1989. Dr. Gharib has two sisters, Nahid Ziai and Mayram Comninos, and one brother, Dr. Mohsen Gharib. In 1976, he married Minoo Jalili and they have three children.
Dr. Gharib grew up in Tehran, attended Ferdowsi Grade School (1946–1952) and later Alborz High School (1952–1958), graduating with honors in 1958. He traveled to the United States in pursuit of the study of medicine. He received a B.S. degree from the Ohio State University in 1962. He went on to receive a medical degree from the University of Michigan Medical School in 1966, and took his internship at Philadelphia General Hospital from 1966 to 1967. He completed an internal medicine residency (1967–1969) and fellowship in endocrinology and metabolism (1969–1971) at the Mayo Clinic in Rochester, Minnesota. After a visiting fellowship in reproductive endocrinology at the Columbia University College of Physicians & Surgeons in New York City, he joined the Mayo Clinic faculty in Rochester in 1972.