I wasn't sure, but my brother's children were physically disciplined and they're the most well behaved, well adjusted kids you could know.
I think if done infrequently and lightly and only when the kids a re really bad its OK. I advise you to abide by the laws of your country if they say its illegal, though. If spanking is being done every day then parents are doing something wrong
Do unto others as you would have them do unto you:-Jesus Christ, Buddha, Confucius,Socrates