"George P. Masologites" wrote:

       In Biology class Akane learns about a Punitt's(SP?) Square. For
those who aren't familiar with that, it's a chart that more or less
indicates what color eyes one's child will have. Akane learns that two
brown-eyed parents cannot have a blue-eyed child (unless both parents are
heterozygotes, which is rather rare).

I don't think this is true.  My mother is Chinese, and thus is obviously
homozygous for brown eyes.  

Genes can be passed down for generations without being expressed.  Also,
brown eyes come in many different shades.

My father is caucasian, and he has brown eyes.
His father is Greek and has brown eyes.  His mother is West European and
has green eyes.

My younger brother has green eyes, but there's no way he could be
homozygous for green eyes because my mother is homozygous for brown.

Eye color variations come from the amount of melanin in the eye.  The
general pattern is black > brown > hazel > green > blue-green > blue >
light blue.  You'll notice that green and brown are not that far apart. 

Furthermore, eye color is controlled by more than one gene.  Even
discounting the possiblility that your mother has green- or blue-eyed
people in her ancestry, the genes your father got from his green-eyed
mother could combine with light-brown genes in his wife to produce a son
with noticably green eyes.  It would be far less likely for your brother
to have blue eyes, because blue and brown eyes are farther apart.

Likewise, it is possible for two light-eyed parents to produce a child
with eyes darker than either of them.  For two blue-eyed parents to
produce a brown-eyed son, however, would be very rare.

As for Akane and her Punnett square, it's true that onna-Ranma's blue
eyes in the anime would probably not come from two brown-eyed Japanese
parents.  But anime hair and eye colors never make sense anyway.  I
mean, look at Chibi-usa.  Her hair is frickin' *pink*!  How the hell do
you get *pink* hair?

-- David