Wolverine's hirsuteness is a result of Canadian hair restorative experiment
code named "Rogaine." He was so embarrassed about his receding hairline
that he asked that his memory be wiped out. While unconscious, he overheard
one of the lab techs speaking about "Rogaine" and somehow assumed that they
were referring to him as "Logan." Forget about that nonsense where he took
the name "Logan" from his former butler or theguy that delivered his milk.
That's the rest of the story.