Humans produce relatively few offspring compared to most other species.
Well-planned breeding experiments are impossible. Our understanding of Mendelian inheritance in humans is based on the analysis of family pedigrees or the results of matings that have already occurred. An important tool to understanding human genetics is the family pedigree which describes the interrelationships of parents and children across generations with respect to a specific trait. This is the reverse of planned experiments since it is analyzing the results of previous mating. Mendel's laws can be used to analyze the pedigree and the genotypes of individuals deduced.