When Dr. Jeff Friedman followed in his father’s path to become a doctor, he entered a six-year medical program out of high school and received an M.D. at the age of 22. After a yearlong fellowship working in the lab of The Rockefeller University's Mary Jane Kreek, he fell in love with the science life. Today, using advanced techniques in neurobiology and genetics, Dr. Friedman has identified and characterized the activity of leptin, a hormone secreted by fat cells that balances food intake and energy expenditure. By studying leptin, as well as other genes that influence weight, Friedman hopes to eventually aid in the development of therapies to combat obesity. Dr. Friedman is a Professor at the Rockefeller University in New York City and Director of the university's Starr Center for Human Genetics. Lately, he has taken his search for fat genes to Kosrae, a small island in the Pacific where obesity is rampant. By analyzing DNA collected from all the adults on the island, Dr. Friedman hopes to learn more about why some people are overweight while others are lean.