Well look what I found ...I can also copy and past a study ...
Cause and the effect
Despite the fervor of anti-spanking experts, the scientific evidence that spanking does cause behavioral trouble later in life is thin. While spanking has been associated with a wide range of negative effects, such as increased aggression, decreased self-control and adolescent depression, the studies can't prove that these effects were caused by spanking. For instance, it may be that aggressive kids with poor self-control get spanked more because their behavior makes their parents angrier. Or it might be that aggressive parents with poor self-control spank more and are also more likely to pass on to their kids genes linked to aggression and poor self-control.
And many of the studies tend not to differentiate between parents who spank frequently and forcefully and those who do so occasionally and moderately. So results get lumped together, with different definitions of "spanking" carrying the same weight.
Such studies only prove that nothing was proved, say Diana Baumrind, Ph.D., of the University of California, Berkeley, and Robert Larzelere, at the University of Nebraska Medical Center, in Omaha, both of whom have been critical of the wide-ranging conclusions reached by many studies of physical punishment. Baumrind, in fact, has conducted research suggesting that "moderate" spanking has no effect on kids' well-being.
Happy pumpkin? ?