Teen dating: it's a subject that causes many parents to shudder and shy away. But romance is a fact of life for young people, and parents can use Valentine's Day to start important conversations with their teens or pre-teens that can make dating and relationships safer for them -- not just now but throughout their lives. The experts at Youth Villages say there's a dark side to puppy love. ■ Approximately one in three adolescent girls in the United States is a victim of physical, emotional or verbal abuse from a dating partner. ■ One in four teen girls in a relationship says she has been threatened with violence or experienced verbal abuse, and 13 percent of teens say they were physically hurt on purpose by a boyfriend or girlfriend. ■ Forty-five percent of girls know a friend or peer who has been pressured into having intercourse or oral sex. These statistics were compiled by the Centers for Disease Control in Atlanta. The Internet, social media and cell phones have opened up new avenues for improper, even illegal behavior, among teenagers. Teens can be harassed or ridiculed through texts or Facebook posts. And one in five teen girls has electronically sent or posted nude or nearly nude photos or videos. What's a parent to do? Kristin Landers, a clinical program manager for Youth Villages, a private nonprofit with the mission to help children with emotional, behavioral and mental health issues and their families, said to help teens date safely, lines of communication have to be open, and parents must pay attention. Here are some tips: -- Know your teen's friends. "As children become tweens and teens, it's more important than ever for parents to know their children's friends," Landers said. "This is the age when what peers think and say are a teen's top influence. Teens value their friends the most. You must know them. "You may have to step in and help the child reduce his or her relationship with a peer who you think is negative or damaging. That's very difficult. It's easier to promote positive relationships early and nourish those relationships through the teen years." -- Set family expectations early and review often. It's never too early to start talking about your family's unique values and expectations. Start talking about dating and relationships as early as age 9 or 10, no later than 12 -- before the first date is even on the horizon. "Your child needs to know what activities you consider appropriate and where the absolute out-of-bounds lines are," Landers said. "Be sure to look for 'teaching moments' -- such as a congressman who is forced to resign after sending a provocative photo. These events become lessons in the bad things that can happen when actions aren't thought through. You can discuss incidents that are in the news, behavior of TV stars, scenes in movies, anything that will inspire conversation and help you reinforce your values message." -- Take a deep breath and discuss sexual situations your teen might encounter. "Remind them that oral sex is sex. There seem to be some teenage and adult misunderstandings about that," Landers said. "Be sure your teens understand that they have the right to say no." You might even role play potential situations so your child learns how to say no, or what to do if he or she feels pressured. -- Randomly check your child's cell phone. Check your teen's cell phone periodically to review the content and tone of those continual texts. You should have the password. "People lived without cell phones for centuries, and your teen might have to now -- if rules are broken," Landers said. "Remind them that sexting is not just offensive -- it's illegal," Landers said. "Make sure your child knows that sending nude or provocative pictures on a phone may bring a visit from police and -- maybe more importantly to them -- will allow the photo to be forwarded to the entire school. Friends who open messages showing a minor in a sexually provocative way may be accused of viewing child pornography." You can use the Internet and multimedia to help you. One website to consider, www.thatsnotcool.org, produced by the Ad Council, offers humorous videos that nudge teens toward the right answers about digital media and relationships. -- Be on the lookout for toxic relationships. Most teen dating relationships go as well as we all expect. There's first love, first breakups, lots of emotion, but very little lasting damage. Like adult relationships, though, teen ones can involve physical or emotional abuse, harassment and stalking. Some have even committed suicide after a romantic breakup. Parents have to continue to be on watch. Look for changes in eating or sleeping patterns, excessive worry or preoccupation with what a boyfriend or girlfriend thinks, a drop in grades and isolation from old friends. Know the boyfriend or girlfriend and his or her parents. If you notice any of these things in your teen, something is wrong, and you need to talk with your child to find out what is going on, Landers said. The teenage years are an important time for any child. He or she is taking steps toward adulthood and making lifetime memories: first date, first crush, first love. "Hopefully, they'll have fond memories of the caring, involved parent who watched over them during this time as well," Landers said.