Justin Richardson, MD, is the coauthor, with Peter Parnell, of the award-winning picture book And Tango Makes Three. Dr. Richardson is an assistant professor of psychiatry at Columbia and Cornell and the coauthor of Everything You Never Wanted Your Kids to Know About Sex (But Were Afraid They’d Ask). Dr. Richardson and his advice have been featured in The New York Times and The Washington Post, on the Today show and NPR’s Morning Edition, and in numerous magazines. Dr. Richardson lectures to parents and teachers on parenting and the sexual development of children.