But the environment alone may not persuade most people to consider having just one child, as eighty percent of Americans have siblings. Powerful stereotypes about only children -- that they're spoiled, selfish, or maladjusted in some way -- still persist. McKibben, the proud father of an only child himself, debunks these myths, citing research about the many emotional and intellectual strengths only children possess. Contrary to the old folk wisdom, only children are very much like everyone else; they are no more likely to be lonely, shy, or difficult to get along with than children with siblings. Only children also receive the benefits of more parental resources and time that are denied to kids with siblings: higher test scores and levels of achievement in school, and greater development of positive personality traits, like maturity and self-control.