Even identical twins, who share the same DNA sequence, have different fingerprints because fingerprints are not solely determined by genetics. While genetics influences the general patterns and shapes found in fingerprints, the specific details that make each fingerprint unique are influenced by environmental factors during fetal development.

Fingerprints develop during the early stages of pregnancy, around the ninth week, when the fetus’s skin interacts with the amniotic sac. The formation of fingerprints is influenced by various factors occurring in the womb, such as the baby’s position, the pressure exerted on the fingers, and random variations in the way skin creases and ridges form due to the intricate folding of the skin as the fetus grows.

These factors lead to small, distinct differences in the minutiae (the ridge endings, bifurcations, and other patterns) within what may otherwise be similar general fingerprint patterns in identical twins. Hence, despite their identical genetic makeup, the unique combination of environmental and developmental factors experienced by each twin results in distinct fingerprints.

In summary, fingerprints are a complex interplay of genetic predispositions and developmental randomness, ensuring that every individual, even identical twins, has unique prints.