Is spanking detrimental to children?

I really enjoyed these articles of contrasting opinions and although my opinion on the subject didn't change, I now look at the debate in a sort of different light. First, It's hard to get empirical evidence on this matter because (1) there are so many other variables to consider as to why kids who were spanked had higher levels of aggression in adolescence and (2) if a researcher was observing parents who spank their kids to collect evidence, at what point is too much and ethical lines are crossed. The interesting thing about the two, however, is that arguement stating spanking was "not" detrimetnal to healthy development seemed to include more facts and statistics than the argument claiming spanking "is" detrimental. The latter argument really didn't place much emphasis on socio-economic status and the violent nature of the parents, if any. The conclusion I came to is that there is no evidence suggesting that not spanking your child will lead to aggressive behaviors, however there really isn't a lot of hard evidence suggesting that spanking your child will lead to aggressive behaviors either. Having said that, I was not spanked as a child (or the recipient of any type of corporal punnishment for that matter) and I still contend I will not spank my children either, for the simple reasoning that I do not believe in inflicting any type of pain to "teach someone a lesson" or "prove who the boss is".