Male and Female, He created them
Forming your children in the Christian understanding of sex. You cannot shelter your children from the world, but you can prepare them for it! If you don't teach your children about sex, someone else will, and no one has the love and good intention of your children in mind like you do!
Erika Dawson points out some valuable statistics on her blog, Faithful Moms:
There is a positive correlation between an open dialogue between parents and kids about sex and sexual abstinence. Feeling safe to talk with you also helps protect kids from sexual abuse
The information your children receive outside the home will likely will be distorted, wrong, too graphic, addictive, or used to lure, shame, or trap our kids. Kids hear more from their friends and through media than we realize — even at 6 years old.
Nearly 60% of 16-18 year olds have sexual intercourse, and nearly one-third of 13-15 year olds have sexual intercourse. Furthermore, 67% of teens who have had intercourse wish they had waited.