Health experts have released a confronting guide to sexual behaviour in children, using a traffic light system to classify everything from masturbation to "sexting".
Is this Normal, developed by Family Planning Queensland, uses red, amber and green coding to advise parents of what is normal behaviour, such as three-year-olds playing "doctors and nurses", and what is worrying such as a 13-year-old obsessed about pornography.
The authors say the guide will help confused parents after reports some fathers were worried about washing their young children in the bath because of fears it could be misconstrued as inappropriate. The guide says there is nothing wrong with children under five asking about or wanting to touch the nude bodies of familiar adults, because it shows natural curiosity.
Holly Brennan, a child sexual abuse prevention expert who helped write the book, said some parents would find it confronting. "There is advice around for professionals but parents have to deal with these issues every day," she said.
Ms Brennan said the wide use of the internet and mobile phones meant parents needed to be particularly aware of the risks if their children sent sexually explicit messages or nude photos of themselves. It was not a harmless part of growing up.
Family Planning WA education consultant Michelle Lambert said parents could get information about their children's nutrition but it had always been difficult to get advice on sexual behaviour.
"The most important thing parents can do is to be open with their kids," she said.
Australian Family Association WA president John Barich said he supported parents and children being given balanced information but he was concerned there was still a basic premise that it was normal for teenagers to engage in sexual activity.
"We're not saying sex is dirty but with so many unwanted pregnancies and sexual diseases around what we need to be saying to young people is that you don't need to be having sex yet," he said.