How to Determine Eye Color in Infants

By Tammy Quinn Mckillip
Like hair color, the color of your baby's eyes is mapped in her DNA.
Like hair color, the color of your baby's eyes is mapped in her DNA.

Don't get too attached to your baby's blue eyes because they are likely to change. Only time and genetics can tell what eye color your child eventually ends up with. Only Caucasian and part-Caucasian babies have blue eyes when they are born; African-American, Hispanic and Asian babies typically start with dark eyes that don't significantly change color.

Enjoy Those Blue Eyes Now

Your newborn's blue eyes are likely to change hue and tone over several months. They may begin slate-gray or deep blue, but over time, melanin in his iris begins to respond to light, turning the pigment in his iris a deeper blue, green, hazel, gray, amber or light or dark brown. Between 6 and 9 months old, your baby's eyes may undergo dramatic color changes. You should be able to predict your baby's basic eye color by the time he is 3 years old, though his eye color may continue to change in subtle ways into adulthood.

Parents' Eye Color

Eye color is determined by a combination of two sets of two types of genes. Each child inherits one copy of each gene from her mother and father, which means there are three possible genetic combinations that determine eye color.

If you and your partner have blue eyes, it's likely -- but not for certain -- your baby will, too. If one of you has blue eyes and the other has green eyes, there is an equal chance of your baby having blue or green eyes. A brown-eyed parent usually has a 50 percent chance of producing a blue-eyed baby if the baby's other parent has blue-eyes, though the gene for brown eyes is dominant if it is carried in both parents' DNA. The same is true for green or hazel eyes.

The Grandparent Factor

Even two brown-eyed parents have about a 25 percent chance of producing a blue, green or hazel-eyed child if one or more of the baby's grandparents did not have blue eyes. The same is true for couples who both have hazel or green eyes and for parents with one of each. The odds are less than 25 percent of having a blue-eyed child when at least one grandparent does not carry the blue-eyed gene in her genetic code -- but odds are just odds. When it comes to determining the color of your baby's eyes, there's really no safe bet.

Different Colored Eyes

Rarely, in about six in 1,000 babies, each eye is a different color. Sometimes the distinction is subtle, and the condition is otherwise benign. Occasionally the baby might have eyes of two distinctly different colors, or heterochromia iridis, which can be inherited or acquired through illness or damage to the eye. This may indicate the presence of other possible problems. Take your baby to the pediatrician and ophthalmologist if her eyes are drastically different shades or colors. The doctor can rule out congenital syndromes and diseases with blood and chromosome testing. If there is trauma to, or an infection of your child's eye, early treatment may prevent further damage.