It is not a Punnett Square, but is often used to approximate parental genotypes from available family data.  
Discovered in 1761 by its namesake, it was brought into its modern form by Laplace.  It is not a Punnett Square, but is often used to approximate parental genotypes from available family data.  Properly understood, it is the fundamental mathematical law governing logical inference--determining what degree of confidence one would have in a hypothesis based on the body of evidence available.  FTP, name this theorem that allows one to apply quantitative reasoning to the scientific method, the fundamental theorem of inverse probability.
Discovered in 1761 by its namesake, it was brought into its modern form by Laplace.  
Bayes' Theorem