Sample size of one:  my youngest preferred my right breast and refused to
nurse in bed while lying on his right side (he wanted to lie on his left
side and nurse from my right breast).  I could fool him into nursing from
the left breast by leaning way over, when he was little, and letting him
still be on his left side.  He had 3 or 4 ear infections during the first
two years of life, always in his RIGHT ear, the one that was on top, and
therefore not being bathed in breast milk during night-time feedings.  I
think that children who nurse lying down don't get ear infections in the
ears that are bathed in breast milk, because of all the anti-infective
properties of breast milk.