 In actual practice, the formula to establish paternity is more complicated (Kaiser and Seber, 1983), but for the sake of illustration, we abstract away from this complexity. Suppose the prior probability that the defendant would be the father is as low as .01, or in symbols, \(\Pr(\textsf{father})=.01\).  Plugging in this prior probability into Bayes theorem, along with \(\Pr(\textsf{m}\pmid \textsf{father})=1\) and \(\Pr(\textsf{m}\pmid \textsf{not-father})=1/1,121\), gives a probability of paternity \(\Pr(\textsf{father}\pmid \textsf{m})\) that is equal to about .92.