title: Blood typing and twin zygosity: a comparison of two methods.
mesh_terms: D001788:Blood Grouping and Crossmatching; D005260:Female; D005819:Genetic Markers; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D008722:Methods; D008957:Models, Genetic; D011247:Pregnancy; D013223:Statistics as Topic; D014427:Twins
chemical_list: D005819:Genetic Markers