Robie Harris, the children’s book author whose It’s Perfectly Normal: A Book About Changing Bodies, Growing Up, Sex, and Sexual Health remains a frequent target of censors, died on Jan. 6 at 83, Publishers Weekly reports.

Harris, a Buffalo, New York, native, was educated at Wheaton College and Bank Street College of Education. She worked as a teacher before making her literary debut in 1977 with Before You Were Three: How You Began To Walk, Talk, Explore, and Have Feelings, co-written with her cousin Elizabeth Levy.

In 1994, she published It’s Perfectly Normal, illustrated by Michael Emberley. The book received praise from critics, including Kirkus, which called it “a terrific teaching tool that just may help slow the spread of sexual diseases and ignorance.”

The reviewer also noted that the book “will be anathema to social conservatives.” This proved correct; the book was controversial at the time and remains so. The American Library Association says that the book was one of the top 10 most banned or challenged titles in 2003, 2005, 2007, and 2014.

Harris’ other books include It’s So Amazing!, Hello Benny!, It’s Not the Stork!, and Mail Harry to the Moon!, all illustrated by Emberley.

Harris was a member of the board of the National Coalition Against Censorship; in a statement, the organization said, “As we mourn the loss of Robie Harris, let us remember her as a beacon of courage, resilience, and passion. Her legacy will continue to inspire us in the ongoing fight against censorship, reminding us of the importance of upholding the principles she held dear.”

Michael Schaub is a contributing writer.