Three proud mothers are discussing their eight-year-old sons. 
"I just know my little Johnnie is going to be an engineer," said the first. 
"Whenever I buy him a toy, he tears it apart to see what makes it work"
The second said, "I'm so proud of Freddie, I just know he's going to be a fine lawyer. He argues with the other kids all the time"
"No question about it", said the third mother, "little Harold is destined to be a doctor, Why, he never comes when I call him!"