Parents who spank their children are setting them up for a lifetime of harmful effects, according to a new warning from the American Academy of Pediatrics.

The nation's top pediatrics group is strengthening its warning against spanking, saying the controversial practice is ineffective and harmful to children.

The group, which represents about 67,000 doctors, based its new policy statement on recent studies that showed spanking is linked to increased aggression and doesn't teach children right from wrong.

The American Academy of Pediatrics also advises against nonphysical punishment, including insulting, shaming or threatening.

Instead, the academy says timeouts work well for young children. As for older children, it says temporarily removing favorite privileges, such as sports activities or playing with friends, is effective. The academy also recommends rewarding positive behavior.