Beating people who are very young is wrong. That seems axiomatic to me. I do not have a medical journal article bookmarked to satisfy your question but can sugg

Beating people who are very young is wrong. That seems axiomatic to me. I do not have a medical journal article bookmarked to satisfy your question but can suggest "On Children and Childrearing" by Henry H. Lindner M.D. http://henrylindner.net/Writings/Childrearing.html http://henrylindner.net/Writings/Childrearing.html