Looking back, Robie Harris says she had never thought about writing a book about sexual health for kids. But today, she is the proud author of three such works (in collaboration with illustrator Michael Emberley): It’s NOT the Stork!: A Book About Girls, Boys, Babies, Bodies, Families, and Friends (Candlewick, 2006); It’s So Amazing!: A Book About Eggs, Sperm, Birth, Babies, and Families (Candlewick, 1999); and the one that started it all, It’s Perfectly Normal: Changing Bodies, Growing Up, and Sexual Health (Candlewick, 1994), which marks its 20th anniversary this month. On September 10, Harris was the guest of honor at a launch event in Boston hosted by her publisher and Planned Parenthood League of Massachusetts (with whom Robie has consulted) to celebrate the release of Candlewick’s updated anniversary edition of the book. “It was such a wonderful evening,” says Harris, “and Boston [Harris’s former home] was where it all happened.”

The seeds for It’s Perfectly Normal were planted around 25 years ago, according to the author. “I was sitting in an editor’s office and he asked if I would want to do a book on HIV/AIDS for children,” Harris recalls. “I was kind of surprised, but then I looked at him and said, ‘Gee, if I were doing a book for kids I would try to answer almost every question kids might have about sexual health. I would do a comprehensive book that includes HIV/AIDS.’ ” From that point, Harris began “spouting out” all kinds of topics as the editor jotted them down. At the end of their conversation, he handed her a list and said, “There’s your book.” Harris notes that “every single one of those topics is in the book today.” (Harris says that the editor who was her brainstorming partner – who has admitted to her that he was “stupid enough not to do the book” – prefers to remain anonymous.)

With the idea firmly planted, Harris decided she wanted to write a full manuscript before submitting it to any publishers. “It’s complicated and complex, and it’s loaded material for many people,” she explains. It was at this early stage that she called on Michael Emberley, a fellow then-Bostonian who she “knew a little bit. I told him I wanted to talk with him about working on a book about sex and sexual health, and he said, ‘I’ll be right over,’ ” she recalls. When they were able to collaborate on a handful of illustrations that were appealing to kids and also provided information, “I knew we were a team,” says Harris.

The pair submitted their manuscript to several houses with the caveat that the project not be significantly altered. “A number of publishers were interested,” says Harris, “but they all wanted to change things.” Candlewick Press, which had recently launched [in 1992] as the U.S. outpost of Walker Books in the U.K., was among the manuscript recipients. Candlewick bought the book two weeks later and Amy Ehrlich became its first editor. As Harris remembers it, “She said, ‘We want to do the book. We support your vision, and want to make it happen.’ ” Though some of Candlewick’s personnel have changed over 20 years, Harris praises her publisher’s unwavering support for and commitment to the book and its successors in what the company has termed “The Family Library.” The three titles combined have nearly two million copies in print.

If landing a publisher proved relatively easy, ensuring that the material in the book was just right took significant effort. “For me, part of the process of writing has been to go to the experts,” Harris says. She began close to home, asking her then-teenage kids to share what was useful and what was left out of their own family discussions about the birds and the bees. From there, she consulted doctors, nurses, psychologists, and numerous scientists, including geneticists and reproductive biologists. “When I first called they didn’t know who I was,” she says. “But no one has ever turned me down. I want to be responsible, and I don’t sleep at night until I know the material is vetted.”

The vetting process, of course, did not stop with the book’s first publication. Harris’s current editor, Hilary Van Dusen, notes that she and Harris typically keep running lists of any information that may need to be changed or updated in preparation for routine reprints that take place roughly every five years. Those updates have been fairly minor over time, according to Van Dusen, but the anniversary edition involved more extensive updates which required some new illustrations by Emberley and additional pages.

“We started probably a year and a half in advance,” Van Dusen says, “and it took a lot of work. It was like a puzzle as we revised text and art, and we were piecing everything together to see how we could fit it all in.” She notes that there was some additional reformatting and design work done “to clean things up a bit” as well. The newest updates include expanded sections on dealing with Internet information and images that may be upsetting, confusing, or inaccurate; information about responsible and respectful use of social media (including “sexting”); expanded definitions for the term “gender,” and the inclusion of transgender youth; updated information on contraception and state restrictions of abortion, information about preventing sexual abuse, and the inclusion of the HPV vaccine for boys. It’s So Amazing!, which celebrates its 15th year in print this year, also received some sprucing up that includes new, updated, and expanded text and art.

“I thought it would take a shorter amount of time,” Harris says of Perfectly Normal’s update. “But kids deserve the most honest, accurate, up-to-date, age-appropriate information you can give them. If you’re not honest when you’re writing, if you hold back, you are doing kids a huge disservice. They will know it, and they’ll stop reading; they will not get the information they need.”

Harris’s approach, and the information she has chosen to provide, do have their detractors. It’s Perfectly Normal has repeatedly appeared on the American Library Association’s list of most frequently challenged books. The author shares the story of a nine-year-old girl who went to the library with her mother and checked out the book. Upon reading the section about sexual abuse, the girl went to her mother and said, “This is me.” As Harris notes, “The abuse stopped. It’s a tragic story. But that child was helped because her mother allowed her to pick any book she wanted from the library, and the librarian had the book in open shelving. That can help kids through the simplest and most devastating things.”

On the subject of opposition to the book, Van Dusen says, “At this point, we are experienced dealing with the challenges that come up,” noting that the company has provided support materials and has assisted librarians in some instances. “It goes with the territory,” she adds. “We stand behind these books 100 percent.”

Candlewick’s marketing for the anniversary edition involves consumer-focused advertising with a group of mom-bloggers and a national publicity campaign targeting parenting and health contacts, which includes a big push for this month’s Banned Books Week (September 21–27). The publisher created a brochure highlighting the updates and changes made to the two anniversary editions and distributed it via the Indiebound white box mailing this summer. As October is “Let’s Talk Month,” a national public education campaign coordinated by the group Advocates for Youth, which aims to help young people make informed decisions about their reproductive and sexual health, it’s also the perfect time for Harris to embark on a national book tour, partnering with Planned Parenthood and Reach Out and Read. Harris will be on the road through early 2015, making stops in New York City, New Haven, Chicago, Denver, Los Angeles, and San Francisco.

“Robie was one of Candlewick’s first American authors with this book,” says Van Dusen. “It’s a foundation of our company. We are proud of that and proud of her. We wanted to make a big deal about the anniversary because it’s a little piece of our history.”

It's Perfectly Normal: Changing Bodies, Growing Up, Sex, and Sexual Health (20th Anniversary Edition) by Robie H. Harris, illus. by Michael Emberley. Candlewick, $16.99 ISBN 978-0-7636-6872-3