Well, taken a random human from the population, what is the probability he doesn't resemble anyone else alive? This is not really a mathematical question, since

Well, taken a random human from the population, what is the probability he doesn't resemble anyone else alive? This is not really a mathematical question, since "resembles" is undefined and it really depends on the biological nature of human morphology, but I'm pretty sure that except for pathologically abnormal cases the answer always will be close to zero.