Before your new baby arrives, you probably dream about what he will look like. Eye color may be one such speculation. However, when your new bundle of joy makes his first appearance, he may not be sporting his permanent eye color. A baby is not born with fully developed melanin in the eyes, meaning his eye color may change over time.
The iris is the part of the eye that contains color. The eye color is determined by levels of melanin in the iris. Melanin is what also determines skin and hair color. The more melanin in the iris, the darker the eyes. Blue eyes are the result of an absence of melanin. According to Burt Dubow, O.D., the iris is actually a muscle. This muscle expands or contracts to change the size of the eye's pupil, which is the black center part of the eye. The iris contracts in high levels of light and expands in darkness. It also contracts when reading or looking at objects near the eye. As the iris expands or contracts, eye color can change slightly.
Eye color is an inherited trait passed down from the baby's parents. According to Dr. Dubow, the eye color of the baby is determined by three separate genes, with only two of those genes fully understood by geneticists. Genetically speaking, brown eyes are dominant over green and blue eyes and green eyes are dominant over blue eyes. Blue eyes are the result of the recessive gene. A baby who inherits a brown-eyed gene from one of his parents would have brown eyes. However, if the baby inherits two recessive genes, the baby could end up with blue eyes. The third trait that is still not fully understood accounts for hazel, gray and eyes of varying combinations. This gene also is cause of some babies having eyes that do not match their parents' eyes, in a genetic sense.
A baby's eye color at birth is not necessarily indicative of her permanent eye color. Dr. Anna Kaplan points out that melanin in the eye is not fully developed in newborns or even babies. The majority of babies will have fully developed melanin by 6 months of age to a year, but not always. In fact, some people have eye color that continues to change well into adolescence and sometimes even adulthood. Typically the eyes will darken over time and not get lighter.
Dr. Kaplan notes that though eyes typically darken over time, lightening can occur in babies. Babies born with dark brown eyes or who develop dark brown eyes during the first year of life will have eyes that stay dark brown. However, babies with blue, hazel, green or light brown eyes can lighten over time. Therefore, it is possible for a baby's eye color to lighten, as long as he does not have dark brown eyes.
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