Re: Why do people get birth marks?

I can't answer "why" except to say that birthmarks are caused by a genetic 
variation and that people get them randomly and without any logical reason. 

Some cultures used to think that a birthmark was a sign that the person 
was special - either special good or special bad.  We now know that 
genetics is pretty random and predisposes people to all sorts of 
characteristics like having brown eyes, dark skin or a certain body build. 
A birthmarks, or hemangioma or nevus (more general terms for birthmarks and 
moles, respectively), are really clusters of capillaries in the dermis (the 
lower part) of the skin.  They are usually not cancerous and can be of several 
types.  Some are outgrown, usually by the age of 7, while others are present for 
a life time.  The more permanent kind is sometimes called a "port wine stain" 
and its coloration depends on how deep the affected capillaries are within 
the dermis.  Laser surgery is sometimes tried as a removal method but is 
not always successful.  They can occur on any part of the body but often 
are found on the face, usually only on one side.  Some cosmetics are useful 
in lightening the color.  While being a source of self consciousness for 
some people, they are harmless in most cases and therefore not a serious 
health threat like so many other congenital anomalies.