1. A method of determining the genotype of a subject at a locus within genetic material obtained from a biological sample from the subject, the method comprising: (A) reacting the material from said biological sample at the locus to produce a first reaction value indicative of the presence of a first allele at the locus within said genetic material, wherein the first reaction value is a measure of the intensity of a first allele-specific quantitative signal; (B) reacting the material from said biological sample at the locus to produce a second reaction value indicative of the presence of a second allele at the locus within said genetic material, wherein the second reaction value is a measure of the intensity of a second allele-specific quantitative signal; (C) calculating a set of probability distributions from a set of input data, wherein said set of input data is obtained under conditions that are comparable to the conditions under which the first reaction value and the second reaction value are obtained wherein said set of probability distributions comprises at least one probability distribution, that associates a hypothetical first reaction value and a hypothetical second reaction value with a corresponding probability for each a genotype of interest at the locus; (D) applying the first reaction value of step (A) and the second reaction value of step (B) to each probability distribution for each genotype of interest within said set of probability distributions of step (C) to determine a measure of a conditional probability of each genotype of interest at the locus, wherein the conditional probability is a measure of the likelihood of the genotype of interest at the locus given the first reaction value of step (A) and the second reaction value of step (B); and (E) determining the genotype of said subject at the locus based on the measure of conditional probability of step (D) of each genotype of interest at the locus for said subject, wherein each allele is a single specific nucleotide.