Smacking children could increase their chances of developing cancer, heart disease and asthma in later life, researchers have claimed.
British psychologists based their findings on a study of 700 adults aged 40 to 60 in Saudi Arabia, where beating is considered an acceptable aspect of parenting.
Those who suffered corporal punishment as children had higher rates of serious disease.
Participants who had cancer were 1.7 times more likely to have been beaten than healthy "control" individuals, according to the research published in the Journal of Behavioural Medicine.
Smacking in childhood increased the chances of heart disease 1.3 times and asthma 1.6 times.
However, independent experts questioned the trend and suggested the findings might be unreliable.
Study leader Professor Michael Hyland, from the University of Plymouth, said: "Early life stress in the form of trauma and abuse is known to create long-term changes that predispose to later disease. But this study shows that in a society where corporal punishment is considered normal, the use of corporal punishment is sufficiently stressful to have the same kinds of long-term impact as abuse and trauma.
"Our research adds a new perspective on the increasing evidence that the use of corporal punishment can contribute to childhood stress, and when it becomes a stressor, corporal punishment contributes to poor outcomes both for the individual concerned and for society."
Corporal punishment was banned in the home and at school by Sweden in 1976. Since then, almost 30 more countries have introduced similar legislation.
Caning at private schools was outlawed in England and Wales in 1999, in Scotland in 2000, and in Northern Ireland in 2003. In the US there is still no universal ban on corporal punishment in schools.