According to a study in "Pediatrics," children who were spanked often were twice as likely as those who weren't spanked to develop aggressive behaviors such as getting into fights, destroying things and being mean to others.
Spanking a 3-year-old could make him or her a bully by the age of 5, according to the study.
That's even taking into account the child's level of aggression.
Many studies have turned up a link between spankings and aggression, but none has controlled for as many factors as this latest one.
An estimated 35 to 90 percent of parents still use spankings as discipline.
This study says parents should focus on positive, non physical forms of discipline such as timeouts.