Additionally, Ober et al.[3] conducted an independent study on a population of American Hutterites by comparing the HLA alleles of married couples. They discovered that married couples were less likely to share HLA alleles than expected from random chance; thus their results were consistent with tendencies for same-HLA alleled partners to avoid mating. Further evidence of the importance of genetic compatibility can be found in the finding that couples sharing a higher proportion of HLA alleles tend to have recurring spontaneous abortions,[4] reduced body mass in babies,[4] and longer intervals between successive births.[5]