There is a huge difference between spanking and beating like others have said. How ever, when you are "spanking" your child, your teaching him the difference between right and wrong. And introducing consequences in their life. Every one must learn the consequences of their actions. Honestly a child getting a swat on the butt is of the most successful means of learning. That is, of course, if you do it ONLY in a disciplinary form. I have an 18 month old son, he would run my life crazy if never gave him a swat on the butt for his wrongs. And I would much rather him learn from me rather than 20 years down the road when he does something and get a big spanking from the law, i.e. JAIL. I Love my son and I want the best for him. He would never learn to appreciate the things he has until he learns the consequences of abusing his privileges. I don't give my son treats all the time, because they are considered to him as a reward. Because he knows if he does good, he gets a treat! If he does wrong, he gets a pow-pow. Hence, learning the consequences.
Don't get me wrong, I don't immediately resort to a spanking. They come when he's exhausted my warnings.
One thing I do know, from being in the child's perspective and the parent's, is please, do not attempted to discipline your child while you are angry. That is where the whooping goes wrong. If you are really upset over what your child has done, step back and take a moment to calm yourself. So you can think more rationally rather than of the adrenaline pumping through you. The fear it will strike your child with, when they see the outraged mama or papa bear coming for them, is anything but healthy. You love your child. That is your baby (blood or not). Why put their beautiful, fragile little minds and hearts through the torment of trying to understand what they've done to deserve it? When you know, once your heart rate lowers, you didn't mean any of it.
Though it is YOUR choice whether you spank your child or not. But if you don't spank and have a good kid, you need to share your secret!