In the U.S. medical students have some practical exposure to medical
treatment and hands-on work in their third and fourth year if they are
attending a traditional med. school.  The students take board exams in a two
parts.  One for the basic sciences taken after second year and the second
exam which includes clinical applications taken in the fourth year of med.
school.

The Board exams, I believe, are to show a basic competency.  Some but not all
of the required clinical practice is obtained prior to the Part two medical
board exam.

After med. school an internship and/or a residency program continues to train
the M.D., who is an M.D. by degree awarded by the medical school,  in a
specialty.  In the U.S. there are not many places to be licensed and practice
after just the internship although several states would allow this, Vermont
being one of them.  Some states allow licensure after two years of
post-medical school hospital training.

My husband tells me that he could, as a neurologist - he is not a
neurosurgeon - even perform surgery if a hospital were to allow him to.  It
is the credentialing process by hospitals that allows physicians to practice
their art within a hospital setting.  An MD could practice medicine in some
states in his private office to whatever extent possible but might run into
difficulties if s/he could not admit patients as in-patients for tests and
procdures and critical care. His patient would have to be turned over to
someone else's care while in the hospital.

It is possible to practice as a specialist in medicine without actually
taking certification exams, although, again this is up to hospitals which
allow some physicians who have finished their residency training to practice
at their hospital prior to passing or taking the certification exam.  Many
ads for MD positions list the requirement as Board Eligible or Board
Certified.

And, like us IBCLCs, my husband as a neurologist first certifying in 1994
must retake his certification exam in five years.  It is no longer a lifelong
certification for the neurologist/psychiatrist tested in 1994 or after.  All
the other neurologists/ psychiatrists previously certified are grandfathered
in.  So neuro has joined the ranks of some other specailties which will
require their new members to demonstrate a continued competency as reflected
by an exam.

I can imagine that a future in lactation could look similar to this:
lactation student -> IBLCE exam -> lactation consultant -> specialty exam ->
 lactation specialist in such and so.

But that does not mean I support this extended path.  Will we need a
standardized education path before taking the IBLCE exam?  Would we ever need
specialists in lactation beyond the wide variety of techniques and
suggestions many of us are already using and discovering/inventing?
  Specialties in medicine emerged when it became too difficult for a single
person to be expert in all systems of the body.  I don't think that we are
anywhere near that point.  There is much to know, much that we will learn in
the future, much knowledge from other fields to incorporate into lactation
but many of us seem to be able to integrate all of it right now and use it to
help breastfeeding mothers and infants.