Tell toddlers what's private about their bodies

Editor's note: Cindy W. Christian, M.D. is the chairwoman of Child Abuse and Neglect Prevention at The Children's Hospital of Philadelphia and a professor of pediatrics at the Perelman School of Medicine at The University of Pennsylvania

(CNN) -- Little of the reported testimony from the Jerry Sandusky trial surprises me. I have heard these stories thousands of times over the past 25 years.

As a child abuse pediatrician, I know how predators lure susceptible children with special gifts or outings, how they coerce and manipulate their victims to comply with their advances, how they ensure secrecy with bribery or threats. I've met thousands of parents whose children were victims of sexual abuse over these years, many of whom were unaware of the crimes being committed against their children, and most of whom were devastated by the knowledge of the abuse.

I've learned lessons along the way, and want to share some weapons that parents can use in the fight against sexual abuse.

Cindy Christian

The first is knowledge. Not the knowledge that child sexual abuse exists -- most parents understand that -- but that child maltreatment is a public health problem that affects millions of children annually, and can have lifelong health consequences for victims.

Opinion: Today, sex abuse victims are less alone

The predators parents have to fear are not nameless stalkers on the Internet, but the friends and relatives who live at home or in the neighborhood. The vast majority of offenders are adults known to a child -- a parent, relative, neighbor, teacher, coach, priest, physician -- someone in a position of power and trust who abuses both. The abuse may or may not involve contact with the child's genitals, and may escalate over months or years.

Sandusky witnesses testify about showers

What will jury do with Jerry Sandusky?

New Sandusky tapes may be trial shocker

Sandusky's lawyer: Trial like soap opera

Parents also need to know that susceptible children tend to be those who are compliant and obedient. They may come from unhappy or broken homes and may be eager for attention and affection. Sexually abused children may not display outward behaviors that are worrisome to families, and if they do, their behaviors are nonspecific. They may appear withdrawn or depressed, or angry or irritable. Their school performance may suddenly and unexpectedly deteriorate, or they may become early adopters of drugs, alcohol or sex.

Jerry Sandusky trial: All you need to know about allegations, how case unraveled

Parents need to know that most child sexual abuse is discovered because a child finally discloses his or her abuse to someone, which underscores the importance of communication, and brings me to talking about sex with young children.

Educating children about privacy, safety and sex starts in early childhood, and is a process, not a talk. So while you are busy teaching your toddlers their body parts, don't forget to name the genitals. Providing a name for them teaches children that their genitals, while private, are not so private that you can't talk about them.

Parents of young children should also teach them about the privacy of body parts, and that no one has the right to touch their bodies if they don't want that to happen. Children should also learn to respect the privacy rights of others. Parents should teach children early and often that there are no secrets between parents and children.

Children need to feel safe sharing all information, good or bad, sad or funny, easy or difficult. As children age, create an environment that allows for open discussion and welcomes questions. Use news items, like the Sandusky trial, to start discussions of safety and to reiterate the message that children should always tell a trusted adult if someone is taking advantage of them sexually.

'The Sandusky 8' describe seduction, molestation and betrayal

If a child discloses abuse, listen carefully, support his or her decision to share. Let children know that the abuse was not their fault, and seek help. That help can come from a call to law enforcement, the local child welfare agency or a child's physician. Know that the discovery of sexual abuse will be a family crisis, and that all affected family members will benefit from counseling and support. Remember that as parents, our best weapons against pedophiles and sexual predators are knowledge and communication. So don't think twice about that sex talk with your toddler.

Follow us on Twitter @CNNOpinion.

Join us on Facebook/CNNOpinion.

The opinions expressed in this commentary are solely those of Cindy W. Christian.