Arly,
You might like to add that although sucking is a reflex activity, integrating
the oral motor skills into the smooth pattern neccessary for optimal milk
transfer is a learned skill requiring organization in the infant.  Since pain
has a disorganizing effect, this integration is hampered, reducing
breastfeeding efficiency.  (This won't work on those dinosaurs that justify
operating on babies' genitals without anesthesia by convincing themselves that
they don't feel pain, but it is true.)
Good luck.
Catherine Watson Genna, IBCLC