So here we are, in 2017, once more having a debate because some people believe it's a good thing to use physical violence against children. And as if that isn't bad enough, some politicians even see it as a way to grab some votes.
Frankly, I find it morally reprehensible we're still having this conversation, but I also understand there is a big difference between making a mistake as a parent, which most later regret, and arguing for the right to intentionally and deliberately use violence against young people.
But there is confusion in many of the arguments, the "n=1" problem. If you were smacked by your parents, and you feel it did you no harm, you may even be right, but your sample size of one (just yourself) proves nothing. In fact it's more accurate to say you are okay, despite being smacked.
As you might expect there's been a ton of research into the impact of smacking, and while controversy exists as to how bad it is, there isn't a single study that shows it improves childhood outcomes.
There are some fairly large "meta-analysis" studies, where the results of many large studies are collected together to understand the overall trends, and these show clearly that spanking, specifically - as opposed to more severe physical violence - is clearly associated with a range of negative behaviours, both as children and later as adults, including increased use of interpersonal violence, aggression, mental health problems and substance abuse.