Jordan Orange, a pediatric immunologist at Columbia University, was not involved in the St. Jude study but helped develop a gene therapy for another immunodeficiency disease called Wiskott-Aldrich.

Parents today also tend to spend more time working, said Dr. Elizabeth M. Fitelson, director of the Women's Program at Columbia University Medical Center.

Dr. Kelly Posner Gerstenhaber of the Columbia Lighthouse Project joins William Brangham to discuss the troubling phenomenon of teen suicide.

“The major thing is, of course, the rapid effect,” said Dr. Margaret Spinelli, a clinical professor of psychiatry at Columbia University.