I just read the inquiry about the 3.5 week old baby boy with
"engorgement", and it made me think of "Witches Milk".  I have seen
babies at their two week well-checks (during my nurse practitioner
training)  with engorged breasts, and my preceptors have always told
me that the babies are having a response to maternal hormones from
their (the baby's) intrauterine life.  Breastfed babies may have a
prolonged response because of the hormones in mother's milk.  It is
benign, and I was always taught to instruct the mothers not to try to
express any of the Withces Milk, and that it will eventually reabsorb
(about 3-4 weeks).  Both boys and girls may experience this
phenomena.  I have always thought it was very interesting.