“Mom, what’s masturbation?” Damn. The sex talk. So soon? You always promised yourself you’d be straight with your kids. No shame, mixed messages, or euphemisms. So why is the word testicles sending you into a fit of nervous giggles? Don’t be anxious. Get help: Raising Healthy Kids: Families Talk About Sexual Health. Produced by an award-winning nonprofit that works with the Center for Disease Control and Harvard Medical School, the two 30-minute videotapes (one for parents of small kids, the other for parents of pre-adolescents and adolescents) tackle all those nerve-fraying sex topics — including anatomical parts, disease prevention, and, yes, touching yourself. Look. You have to do it eventually. And CDC research shows that talking to your kids about sex does not encourage them to have it sooner; it actually significantly lowers their risk of disease and unwanted pregnancy. Remember: If they don’t hear it from you, they’ll hear it somewhere else. And do you really want your kid’s first brush with sexuality to be Missy Elliot? To buy videotapes or read excerpts, go to abouthealth.com.