That's quite interesting. It suggests that there are really three determiners of our attributes: nature, nurture, and... chance! Chance plays a role in nurture (which chromsomes you get, mutations and errors, etc.) and in nature (disease, injury, etc.), but it seems like embedding it in those other two does not do it justice-- when there is no identifiable factors in either nature or nurture that control your fingerprints, chance needs a designation of its own as well. One wonders-- what other attributes are like fingerprints? Aspects of intelligence, for example?