A new law on smacking children has come into force in England and Wales.
Parents who smack their children so hard that it leaves a mark could face up to five years in prison but mild smacking will still be allowed.
A similar law that bans heavy smacking is already in force in Scotland.
But the child protection charity, the NSPCC says the new law is confusing and has called for a complete ban on all forms of smacking.
Head of the NSPCC, Mary Marsh said, "Defining acceptable ways to hit children should become a thing of the past. It should be just as wrong to hit a child as it is to hit an adult."
The NSPCC is worried that the rules do not do enough to protect children.