Twins do often have very similar fingerprints, sharing similar patterns and shapes like Whorls, Loops, and Arches. But no two sets of fingerprints are alike, including those of identical and fraternal twins. About.com explains it nicely when they discuss that "The ultimate shape of fingerprints are believed to be influenced by environmental factors during pregnancy, like nutrition, blood pressure, position in the womb and the growth rate of the fingers at the end of the first trimester." So if twins were to have the same fingerprints, they would have had to have had identical food intake, fluid intake, identical movement, and identical positioning in the womb over the entire nine months. This is why you will find that they do have "similar patterns of whorls and ridges in their fingerprints since they share their DNA...but there will also be differences -- just as there are differences between the fingers on any individual's hands."
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