When I say that children should be told about sex, I do not mean that they should be told only the bare physiological facts; they should be told whatever they wish to know. There should be no attempt to represent adults as more virtuous than they are, or sex as occurring only in marriage. There is no excuse for deceiving children. And when, as must happen in conventional families, they find that their parents have lied, they lose confidence in them, and feel justified in lying to them.
Our Sexual Ethics (1936)