"Random university publishes half-assed study with poor controls and a small sample claims possible implications which can not realistically be measured accurately" is pretty much the alternate title of them.

I can't even remember having been spanked as a kid though my mother tells me she tried it a few times and a bit more with my elder sister, and neither of us grew up to be criminals or bad citizens, so I'm hardly an advocate of 'spare the rod, spoil the child' but lets not go throwing around implications that real hard science has proven that corporal punishment is never useful and always harmful, because it hasn't.