As the sex-positive mother of two tween daughters, I thought we'd already had The Talk a few times. Then, on an ordinary Tuesday afternoon, I found a Google search on my kids' iPad for "people having sex videos."

"WHO DID THIS?!" I yelled, summoning the girls into the kitchen for an emergency interrogation. My questions were met with vehement denial, and even after I changed my approach to playful cajoling, nobody would own up to the search. I didn't press the point, not wanting to shame them or create further mistrust. In hindsight, I wish I'd waited to react, rather than unleashing my fear in the moment.

But I was scared of what they might find online. Looking at pornography in the 21st century can be a disturbing experience for kids, far more lurid than the Penthouse magazine I sneaked at the corner store with my friends in the 1980s. I wanted my daughters to discover a healthy, embodied sexuality in adolescence, rather than rely on pornography for education, which, as Peggy Orenstein has shown, is common practice for many girls.

Luckily, the parental controls I'd set on the girls' iPad worked: The search didn't turn up any explicit content. After I calmed down, I explained to them that the internet can be a dangerous place, but wanting information about sex is natural and healthy. "I'm always available to answer questions or just talk," I promised, an overture met with much eye-rolling. Then I took action and filled their shelves with good books.

"Are You There God? It's Me, Margaret." by Judy Blume
The iconic 1970 novel is still a relevant rite of passage, brimming with humor and compassion. Sixth-grader Margaret Simon moves to a new town, where she joins a secret girl club and longs to fit in. Blume's crisp narration follows Margaret as she goes bra shopping with her mother, endures co-ed square dancing in gym, stuffs her new bra with cotton balls, starts wearing deodorant, learns a hard lesson about sexual gossip and finally, gets her period at the end of the book. "How can I stop worrying when I don't know if I'm going to turn out normal?" Margaret asks, a question that sums up the preteen experience. Age 10 and up.

"The Period Book: A Girl's Guide to Growing Up" by Karen Gravelle and Jennifer Gravelle
A compact manual to accompany Judy Blume, "The Period Book" offers essential information and charming illustrations. Starting with the basic changes of puberty, the two authors (an aunt and her 15-year-old niece) talk about menstruation in a friendly, straightforward tone. They troubleshoot common problems, such as what to do if you bleed through your pants (casually tie a sweatshirt around your waist), and offer shame-dispelling Q&A about mismatched breast size, period clots and more. The updated body image section urges girls not to compare their bodies with those of friends or celebrities. Unfortunately the final chapter about sexuality reads like a warning label, but "The Period Book" is still useful for girls ages 9-11.

"It's Perfectly Normal: Changing Bodies, Growing Up, Sex, and Sexual Health" by Robie Harris and Michael Emberley
A picture can be worth a thousand . . . awkward sex conversations. Much more than the usual sperm-and-egg story, "It's Perfectly Normal's" lively illustrations reinforce the authors' respectful discussion of sexual health. Peopled with bodies of all colors, shapes and sizes, this image-filled guide also covers sexual desire and feelings, homosexuality, pregnancy, childbirth, decision-making, STDs and sexual abuse. I loved the no-nonsense chapter on masturbation, as well as the messages of consent repeated throughout: "Every person has the right to say no to any kind of sexual touching." Caveat: My fourth-grader dismissed this book as "weird," not liking the little bird and bee characters that make jokey comments. Ages 10 and up.

"The 'What's Happening to My Body?' Book For Girls" by Lydia Madaras, with Area Madaras
Full of reassuring straight talk for preteens and teens, this bestseller is also peppered with girls' real-life puberty stories. The ho-hum illustrations can't compete with those in "It's Perfectly Normal," but the anatomy chapters deliver accurate information with empathy. "Your Breasts: An Owner's Manual" explains the five stages of breast development and "Your Vulva: A Guided Tour" covers genital geography, suggesting girls use a mirror to learn about their bodies. Some material feels woefully dated, like the section on romantic feelings that muses "Is it all right for a girl to ask a boy out?" Although "The 'What's Happening to My Body?' Book For Girls" is now out of print, it's worth hunting down. Ages 10 and up.

"Changing Bodies, Changing Lives: Expanded Third Edition" by Ruth Bell et al
This thoughtful, candid sex book for teens was my undisputed favorite, modeled on the classic "Our Bodies, Ourselves." Ruth Bell and her team are members of the Boston Women's Health Collective that authored the pioneering sexual health guide in 1976, and they interviewed hundreds of teenagers to fill "Changing Bodies" with teen voices, poems and cartoons. The comprehensive chapters emphasize healthy relationships - with oneself and others - and encompass emotional and physical health, eating disorders, substance abuse and much more (giving detailed lists of resources). Pleasure-positive, LGBTQ-friendly and astutely feminist, the authors provide a wealth of practical knowledge while encouraging readers to think deeply about their sexual choices and "get to know themselves as sexual people." Appropriate for precocious sixth-graders and beyond, this book is the resource I wish I'd had growing up. It empowers girls (and boys) to make informed decisions and figure out who they are. Ages 12 and up.