If you were smacked as a child and it did you no harm - you probably will smack your own children.
If you were not smacked as a child and it did you no harm - you probably won't smack your own children.
Seems to be the general concensus. I dont have kids, but if I did id keep physical discipline for the most severe of cases....
i.e. "slap" dont put your fingers in the plug socket....
Most other things I think can be dealt with by other means, if you have the time, patience and willingness to carry out threats. (non violent of course)