Virginia Johnson, part of the husband-wife research team that transformed the study of sex in the 1960s, has died.
Her son, Scott Johnson, says his mother died Wednesday at a St. Louis assisted living center. She was 88.
Johnson was a twice-divorced mother in her 30s when she went job-hunting at Washington University in St. Louis in the late 1950s to support her young family while she pursued a college degree.
She soon became an assistant to obstetrician-gynecologist William Masters, and later his lover and co-collaborator on a large-scale human sexuality experiments.
Their books, 1966's "Human Sexual Response" and 1970's "Human Sexual Inadequacy," were best-sellers.
They married in 1971 but divorced after 20 years. The Masters and Johnson Institute in St. Louis closed in 1994. Masters died in 2001.