Babies are born with blue eyes because they have lower levels of melanin, the pigment that gives color to the eyes. As a baby grows, their melanin production increases, which can cause their eye color to change. This is why many babies are born with blue eyes that later turn brown, green, or hazel as they get older.

When born and during the first months of life, babies have a blue-grayish eye color, regardless of their parents' eye color. But why does this happen? The main reason is that the melanin-producing cells, responsible for the color of the skin, eyes, and hair, are immature and produce little pigment.

The eye color will darken until reaching its final color at 6 to 9 months of age, although the shade may still change in the following months. The final eye color is determined by genetics, but external factors like light can also influence it. Additionally, a newborn's eyes are light because they have been in darkness inside the mother's womb during the first months.

When we talk about eye color, we are actually referring to the pigmentation of the iris. The iris has muscles that adjust to control the amount of light, similar to a camera's diaphragm, which we perceive as black even without pigmentation.

If the melanocytes secrete a small amount of melanin, the baby will have blue eyes. If, on the other hand, the amount is slightly higher, the eyes will be green. But if the secretion is greater, the eyes will be brown or black.

The myth of eye color related to breastfeeding

Many people believe that a child's light eye color is due to breastfeeding, but that is not the case. What actually happens is that the duration of breastfeeding coincides with the stage of eye darkening due to the maturation of melanocytes in the baby, but it is not related to the type of feeding.

The likely reason for the emergence of this myth is that during the first months, babies were usually exclusively breastfed, a time that precisely coincided with the lack of definition in the color of their eyes.

Mendel's Laws and eye color

These laws are based on a set of basic rules about genetic transmission from parents to offspring. Eye color is determined by genes, with dark colors being dominant genes and light colors being recessive genes. But it all depends on the pure genes.

It is most common for a baby to have the same eye color as both parents if they have the same eye color. The most common eye color is brown, and the least common is green. Between brown and gray eyes, there are many possible shades, depending on the melanin deposited in the iris and the structure of the eye itself: gray, blue, green, hazel, dark brown, and even violet or certain peculiarities like heterochromia or one eye of each color.