Twins and Hair Colors

Twin girls with long hair and brown hair colors
Photo: Depositphotos
Q: Can twins have different hair colors?
A: The full answer to this question is this:
It depends largely on a variety of factors. Twins are when two children are born from a single birthing to the same mother. Most people when they think of twins think of identical twins who are - in effect - copies of one another since they have the same genetic blueprint and are the result of a single fertilized egg that splits into two individuals.
Yet, there are twins that are the result of the fertilization of two eggs at practically the same time and each egg grows into its own baby. These twins are known as fraternal, and can have very different genetic make-ups because they are formed from separate sperm and egg combinations.
In identical twins, there can be minor differences in the appearance of the individuals, but these aren't commonly very pronounced differences. Perhaps one twin will have a mole that the other doesn't. Yet, different hair color is very rare for identical twins as far as the hair color with which they were born.
Of course, the environment can have an effect on the look of the hair. If one twin spends more time outdoors in the sun, the hair can become lighter than that of his or her counterpart.
With fraternal twins, the hair color can be wildly different since the genetic mapping for one twin doesn't necessarily match that of the other twin. Of course, if a certain hair color is dominant in a family, it would be common to see the twins with the same hair color, regardless of other differences. But having a similar hair color for a fraternal twin is no more likely that for any other type of sibling relationship.
So, you have your full answer to the question, but you can boil it all down to say that "Yes, twins can have different hair colors."
See also:
Hereditary hair color
Psychology of hair colors
The 4 basic hair color categories
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