Unfortunately, for many parents, the most important conversations are the hardest. Ninety-three percent of adults are dissatisfied with the sex education they received as children, which is precisely why they are so bad at teaching their kids-they have no frame of reference. Renowned Harvard Medical School psychologist and frequent Dr. Phil guest John Chirban helps parents talk to their kids . . . about sex.

Kids are going to learn about sex, and it is up to parents to decide if their kids...