Priscilla -- I would definitely read up on and talk about the "hormones of
love" -- oxytocin and pitocin.  This is hard, scientific, factual
information about how these hormones, secreted in lactating mothers but not
in formula-feeding mothers, affect the mother's feelings and attitudes
towards her offspring.  Look for Niles Newton's work, but also something
from the New York Academy of Sciences, a whole volume on oxytocin from the
early 1990s.

Kathy D.