Re: What causes Freckles?

Josh-That's a good question!  The major human pigment is called melanin and 
it is produced by cells in the skin called melanocytes.  Melanin production 
is controlled by genetics as well as exposure to sunlight.  If a person is 
dark skinned, then his/her melanocytes are metabolically more active and 
make not only more melanin but also a darker variety of the pigment.  
Everyone except albinos have the ability to produce melanin.  When a 
person is exposed to sunlight, the melanocytes are stimulated to make more 
melanin.  Evolutionary biologists think this is due to the protection from 
harmful U.V. radiation that darker skin affords to dark skinned people.  
Since we think that the first humans lived in very sunny areas, it makes 
sense that those people who didn't die of skin cancer(caused by too much 
sun exposure) would be the ones to pass their genes on to their offspring. 
 Freckles are small patches of melanin the accumulate in the skin and can 
be made more noticable and more abundant by sun exposure.  They are more 
usual in light skinned people, particularly people with reddish hair.  This 
is due to genetics and freckles don't seem to play any role in disease or 
in any other aspect of one's life.  They neither harm nor help - they just 
are!!  If you have them, enjoy them as many people think that they are nice 
looking.