> Children being born today are some of the first to have parents that even understand what child abuse is
I disagree. Even the most base animals have instincts to care for their young, no? I find it hard to believe that all parents, before a certain time, were unaware of abusive/non-abusive behaviors.
I find it more likely that there is a subconscious instinct to protect one's offspring, and this instinct may exist in people to different extents.