"Class/type similarity" means that twins are likely to, say, both have whorls on their right index fingers, but doesn't mean they'll have the same pattern of ri

"Class/type similarity" means that twins are likely to, say, both have whorls on their right index fingers, but doesn't mean they'll have the same pattern of ridges. So for the sake of biometrics, that doesn't make them more similar than two random people.