Stella Chess, who died Wednesday at 93, devoted her long career in child psychiatry to challenging the notion that children’s personality problems are caused by bad parenting.

Together with her husband and research partner, Alexander Thomas, she used a groundbreaking decades-long study of children to show that mental health is the result of a complicated interplay between an infant’s inborn temperament and parenting style. The result was an important challenge to the earlier orthodoxy, which held that an infant at birth was a blank slate and that mental problems could be chalked up to defective parenting; for instance, autism was blamed on “icebox” mothering.

“It was unprecedented, especially studying children who did not have a disease,” the director of the New York University Child Study Center, Dr. Harold Koplewicz, who worked with Chess over the past decade, said. “Temperament is now taken as a normal convention.”

Chess and Thomas met at the New York University College of Medicine, were married in 1938, and soon became collaborators.

Among the books they published were “Your Child Is a Person: A Psychological Approach to Parenthood Without Guilt” (1965), “The Origin of Personality ” (1970), and “Know Your Child: An Authoritative Guide for Today’s Parents” (1987). Chess and Thomas were unusual in psychiatry for publishing popular books despite being involved in clinical research, Dr. Koplewicz said.

In “Your Child Is a Person,” they insisted, “Prevailing psychoanalytically based theories of child care are wrong.”

They went on to check off the list of Freudian pitfalls: toilet training, thumb sucking, and weaning. Rather than representing some kind of trauma, they wrote, each was a normal part of childhood development. Of toilet training, they wrote, “It seems incredible that a task accomplished routinely in most of the civilized and uncivilized world for a very long time could create so much worry in 20th century Americans.”

Chess was born in Manhattan to parents who were Russian immigrants. Her father became a lawyer and her mother a schoolteacher who was said to have helped create the concept of maternity leave when she brought a suit against the New York City Board of Education in 1911 for terminating her when she was pregnant.

Chess studied at the Ethical Culture School and Smith College before entering the NYU medical school in 1935. In addition to a private practice in Manhattan, she held various appointments, including psychiatrist at the Northside Center for Child Development. In 1954, she became the first professor of child psychology at New York Medical College. She later founded the first pediatric psychiatry unit at Bellevue Hospital and was a professor at NYU.

“Preventive care concentrated on changing the mother’s or father’s behavior, and cultural influences were often ignored,” Chess wrote in the Harvard Mental Health Letter in 1997. “But it became clear that some children with serious problems had adequate or excellent parents.”

Begun in 1956, the New York Longitudinal Study of Child Development followed the lives of 238 young people, just over half of them middle-class whites and the rest poorer Puerto Ricans.

Based on the study, Chess and Thomas delineated three basic temperaments that were present from birth: “easy,” “difficult,” and “slow to warm up.” They identified nine temperamental qualities, such as level of physical activity and distractibility. The trick, they said, was the “goodness of fit” between parenting styles and the child’s temperament.

Seeking to look beyond bad parenting as a cause of autism, Chess in 1971 published “Psychiatric Disorders of Children with Congenital Rubella.” According to Dr. Koplewicz, rubella is no longer suspected of causing autism, but the idea that autism might be an organic brain disorder was “decades ahead of its time.”

Chess and Thomas continued to publish well into what would be retirement for most. Their last book was “Goodness of Fit” (1999).

Thomas died in 2003, and Chess continued to work at NYU, rejecting emeritus status in order to stay involved in day-to-day research. The staff found out she had died because she didn’t show up for work last week, Dr. Koplewicz said.

Stella Chess

Born March 1, 1914, in Manhattan; died March 14 at St. Luke’s Hospital in Manhattan; survived by two sons, Richard and Kenneth, six grandchildren, and four great-grandchildren.