How about alcohol tolerance of redheads? Or temperature sensitiveness? How many special treats are associated with inglorious MC1R protein?
Several studies proved people with red hair (natural or dyed) act significantly different than everybody else, but their behavior could be influenced by the heavy mixture of historical and cultural heritage.
On the other hand, pain and amount of medication needed to suppress it are undeniably measurable. What a so-called hard science says about natural redheads and pain?