A Northern California school district is shelving a controversial sex education textbook with racy references to masturbation, sex toys and bondage.

The Fremont Unified School District acted Friday after outraged parents gathered 600 signatures on a petition calling the book extremely inappropriate for 14-year-old ninth-graders.

Superintendent Jim Morris said in a statement the book “Your Health Today” was being put on hold pending further vetting from parents. Morris also said the book’s publisher, McGraw-Hill, has offered to modify that text to meet student needs and address parental concerns, the San Francisco Chronicle reported.

“I feel that it’s not age appropriate for these kids,” parent Asfia Ahmed told the paper. “I have read the book from first page to last, and most pages talk about college kids. It doesn’t relate to these kids at all.”