When are fingerprints formed?

Fingerprints are formed during fetal development, specifically around the 10th to 16th weeks of gestation. The unique patterns of ridges and grooves on fingers are influenced by genetic factors as well as environmental factors in the womb, such as the positioning of the fetus and the amniotic fluid. This means that by the time a child is born, their fingerprints are already fully developed and unique to them. The formation of fingerprints before birth is crucial because it explains why identical twins can have distinct fingerprints, despite sharing the same DNA.