Computer analysis of parentage in relation to maternity and paternity.

General formulas for statistical calculations of parentage by means of blood group analysis are presented in relation to those of maternity and paternity. Based on these formulas, a computer program has been devised to calculate plausibilities, exclusion probabilities, and distributions of log (Y/X) of parentage for any blood groups. The program also gives numerical values of these quantities of maternity and paternity. The values of plausibility and exclusion probability are highest for parentage, and decrease in the order of paternity and maternity. Concerning the distribution of log (Y/X) for true families, a simple relation holds for the ratio of the mean value of log (Y/X) in parentage ap, to that in paternity af, and to that in maternity am as, ap: af: am = 1: 0.6: (0.6)2 This relation holds for all 14 blood groups examined.