is the almost universal insistence that any overtly expressed sexual notions on the part of little children are signs of sexual pervertion, and the notion that the kids expressing this will grow up to be sexually perverse adults.
Nothing could be farther from the truth, as sexuality is a normal part of human growth, no matter what the age, and, more importantly, the repression of said sexuality is actually the cause of a lot of sexual "malfunction" in later life.