What do you say to your daughters when a young woman vanishes from their college town and was likely the victim of foul play?

My daughters live in Charlottesville, Va.—one enrolled at the University of Virginia and the other a recent graduate. On Sept. 13, less than a month after the start of fall semester, sophomore Hannah Graham disappeared from downtown Charlottesville after a night of partying with friends.

For reasons we may never know, she left a bar alone and hasn't been seen since, other than on grainy surveillance tapes. She was last heard from when she texted friends to say she was lost. In the weeks since then, law officers and searchers have combed the areas in and around Charlottesville looking for any sign of her, but, so far, nothing.

Police have made an arrest and have evidence they say connects the suspect to at least one previous disappearance of a young woman in Charlottesville. Still, the mood on campus remains more somber, more cautious than normal.

I urged my daughters to be careful and not walk alone at night. My younger daughter replied that she was too much of a baby to ever do that. Thank goodness.

What else can a parent say? The Boston Globe recently ran an article urging parents to have "the talk" with their teens. Not the safe sex talk, but the sexual assault talk. Your kids may roll their eyes and appear to ignore you, but experts say that teens may be more willing to reach out for help if they know the lines of communication are open. And, as parents, we may best know what resonates with our children.

Not sure how to get started?

Here are some topics you may want to touch on in "the talk":

• Make sure both girls and boys understand what "consent" means.
• Discuss campus safety options, like safe rides or escorts, emergency phones and crime reporting procedures.
• Talk about campus medical and mental health services and the university staff that may be available to help, from resident advisors and student deans to campus police.
• Provide information about national hotlines that offer help with things like physical or substance abuse or anxiety and depression.
• Talk about how sexual assaults most often occur between people who know each other. Discuss what your child can do to be safe in social and dating situations.
• Rather than telling your teens not to go to parties or drink or do drugs, discuss the potential consequences of those actions. Talk about what they can do to avoid being vulnerable, like never leaving a drink unwatched and having a buddy system to make sure they get home safely.
• Emphasize that if something does occur, it is never the victim's fault. Tell them they can always come to you when they need help or feel uncomfortable about a situation involving them or someone they know.

And remind them to always trust their gut.

Will "the talk" help? It's hard to say. Some awareness campaigns do succeed—such as efforts to reduce smoking and drunk driving. If we all work together, maybe campuses will become safer places for all students.

Still, I remember what it was like to be 18 and invincible—when nothing could possibly happen to me, no matter how many stupid things I did. I know that sometimes I was lucky. And I only hope and pray that my daughters will be so lucky.

For more on ending campus sexual assault, visit Culture of Respect.