Now, I've been hesitant to throw out an anti-spanking study link because the last time I did that someone (krylo?) threw out a study that basically said that due to genes kids are pre-fucked from birth regardless of what parents do, but in searching for the link I stumbled on
this page of nothing but anti-spanking studies. So yeah.
Also,
this one section might be of particular interest to blues and krogo and others along those lines.