Lisa,
I have seen several moms with bisected nipples, one of whom had no difficulty
once we straightened out all the management issues and she gained some
confidence.  The other seemed to have missing ducts, there was one segment of
the areola that was "empty" on palpation, directly associated with the
smallest, most abnormal portion of the nipple. (raspberry is a good
description). It seemed that several adjacent ducts were blind, their sinuses
having never developed.  She had difficulty getting the baby to take that
breast and had engorgement in the lobes missing sinuses until they regressed.
 She is still lactating, and is mostly pumping that breast.  We had discussed
unilateral lactation, but she would like to reduce her breast cancer risk.  I
did counsel her to be especially scrupulous when doing breast self exam on the
involuted portions of the breast, because we don't know if there is an
increased risk a la the totally unsuckled breast.  Oh, interestingly: this mom
told me her dad had one nipple exactly like hers, same side and everything!
        We do see a skewed population, self-selected because they are already
having bf difficulties, so we are more likely to see malformations,
ankyloglossia, and other problematic conditions. I try to be really low key
and matter of fact with the moms and tell them what their condition is called
and how it came about (if known), and how it might impact/be impacted by
breastfeeding. I think being calm and accepting and giving the mom the facts
or theories puts her in control and lets her know she is not weird or alone. I
kind of fell into this approach when a mom I was seeing for engorgement asked
me what the strange swellings in her axillae were (they were accessory
breasts, complete with tiny nipples, which had never been apparent before
lactogenesis.) I calmly explained about the milk line and that sometimes
tissue persists rather than regressing, and that it is not uncommon. She must
have felt comfortable with the explanation, because she let me take a
photograph.  I'd be interested to know how others handle the psychosocial
aspects of breast anomalies.
Catherine Watson Genna, IBCLC