A new study continues to add to the pile of research that suggests that parents who spank risk harming not only their child’s bottom, but also their future.

Children who were spanked more than twice a month were 50 percent more likely than those who weren’t spanked to develop aggressive behaviors. These bullying behaviors included things such as getting into fights, exhibiting mean behavior toward others, and destroying toys and property.

The new study comes from researchers at Tulane University, who examined three year-old children whose mothers reported spanking them more than twice a month. The research was correlational in nature, so it could not establish a direct causal relationship with aggression. However, unlike prior research into this behavior, the new study took into account how aggressive kids were to begin with as well as other factors could have biased the results.

“This evidence base suggests that primary prevention of violence can start with efforts to prevent the use of corporal punishment against children,” noted Catherine Taylor, PhD, MSW, MPH, of Tulane University School of Public Health and Tropical Medicine in New Orleans, and colleagues.

Despite research that demonstrates the negative impact of repeated spankings of children, most parents still believe in corporal punishment. For instance, in a 2005 U.S. poll, 72 percent of adults said it was okay to spank a child.

“Causality is extremely difficult to prove,” Taylor told one news agency, but noted that “the evidence is at a point where we want to encourage parents to use techniques other than spanking that can actually lower children’s risk for being more aggressive.”

The study relied on mother’s self-report of their spanking behavior. Mothers were asked to provide information on their use of corporal punishment, their child’s aggressive behavior at ages 3 and 5 years, and several other related variables.

Overall, 45.6% said they never spanked their child, 27.9% reported spanking their child once or twice in the month preceding the interview, and 26.5% reported spanking their child more than twice in the previous month.

Increasing frequency of spanking was also associated with greater levels of several maternal parenting risk factors. These included physical and psychological maltreatment of the child by the mother, neglect, maternal exposure to intimate partner violence, and maternal stress, depression, substance use, and consideration of abortion.

The study adds to the existing research which demonstrates a number of negative effects in exposing children to repeated physical punishment.

The study is published in the May issue of Pediatrics.