Why do we have fingerprints?

Fingerprints are ridged patterns that form on our fingertips. They develop and are completely formed by the seventh month in utero.

We keep our uniquely individual fingerprints for life. Several factors influence fingerprint formation. Our genes influence the patterns of ridges on our fingers, palms, toes, and feet. These patterns are unique even among identical twins. Twins with identical DNA will still have unique fingerprints. The location of the fetus in the womb, the flow of amniotic fluid, and the length of the umbilical cord are all factors that play a role in the shaping of an individual’s fingerprints.

Fingerprints consist of patterns of arches, loops, and whorls. These patterns are formed in the innermost layer of the epidermis known as the basal cell layer. The basal cell layer is located between the outermost layer of skin, called the epidermis and the thick layer of skin that lies beneath and supports the epidermis, known as the dermis.

Basal cells constantly divide to produce new skin cells, which are pushed upward to the layers above. The new cells replace older cells that die and are shed. The basal cell layer in a fetus grows faster than the outer epidermis and dermis layers. This growth causes the basal cell layer to fold, forming a variety of patterns. Because fingerprint patterns are formed in the basal layer, damage to the surface layer will not alter fingerprints.