Eye color is determined by genetics. One specific chromosome is largely responsible for determining eye color. It carries two genes, one that determines the amount of melanin in the iris, and the other that controls the activity of the melanocytes. These genes act together in determining eye color. If you have a baby with different-colored eyes, talk to your pediatrician. Your child may also need to see a specialist called an ophthalmologist. It's likely that your baby is still developing, and their eye color may be changing naturally.