Abstinence only education, which I've gone at great length in this blog to show you how destructive and counter-productive it is, should not be taught to children because it's incomplete, it's usually false, and it doesn't help prepare children for adulthood. Withholding information is NOT the same as helping teach skills. Sex is a skill, like all other skills we learn as we get older, like paying bills, applying for loans, getting our car's oil changed. When we don't teach children facts about these skills, they make major mistakes that could last a lifetime.
Comprehensive sex ed saves lives. It saves us the financial and legal troubles of helping teenagers when they accidentally become pregnant, when they need surgery to control the consequences of untreated sexually transmitted infections, the mental health care that is necessary when people are abused, mistreated, and have low self-esteem. Even your child's doctor is in agreement!