Children who are punished by spanking are more likely to be abusive towards their partners in later life, claims a new study.
Nearly 800 young adults were involved in research which looked at whether being hit as a child resulted in more aggressive tendencies as a grown up.
It found that hurting a child led to more aggressive behaviour and that most adults who are violent in their relationships were struck as a youngster.
The study, from the University of Texas Medical Branch, asked 19 and 20-year-olds how often they had been spanked, slapped or struck.
Researchers found that, of the 758, children who had been punished with physical violence were much more likely to become aggressive with a future romantic partner.
Data from the study found that nearly one in five (19 percent) admitted to violence towards their lovers.
While 68 percent claimed to have experienced corporal punishment as a child.
The study's lead author, Jeff Temple, a psychiatry professor at the University of Texas Medical Branch, said that they had to determine what they considered punishment and what they considered abuse.
Speaking to CNN, he said: "We defined [child abuse] as being hit with a belt or board, left with bruises that were noticeable or going to the doctor or hospital.
"Kids who said they had experienced corporal punishment were more likely to have recently committed dating violence."
The study found it was not just children who had been abused with physical violence who turned out to be aggressive in later life.
Spanking as a form of punishment was enough to increase violent behaviour in adults.
The participants had been part of an ongoing scientific trial in Texas since they were mid-teens.
The trend to become violent in adulthood was true regardless of sex, age, parental education, ethnicity and childhood abuse.
Researchers controlled these factors in their analysis and found that they made no difference.
Hitting a child as a form of chastisement has been outlawed in several countries across the world such as France, Scotland and Sweden.
There are stringent guidelines in many countries relating to the use of smacking.
In the UK, it is unlawful for a parent or carer to smack their child, except where this amounts to 'reasonable punishment'.
This defence is laid down in section 58 of the Children Act 2004.
The defence of reasonable punishment is not valid in the case where the punishment "amounts to wounding, actual bodily harm, grievous bodily harm or child cruelty."
In the US, it is legal to hit a child in all fifty states and the District of Columbia, but states differ widely about what precisely is allowed.
Enforcement of the law often depends on the discretion of prosecutors.