Heart Defects, Congenital, Male, Genotype, Intelligence, Turner Syndrome, Environment, Chorionic Gonadotropin, Clomiphene, Congenital Abnormalities, Embryonic and Fetal Development, Hemoglobins, Pregnancy, Intellectual Disability, Infant Mortality, Diseases in Twins, Birth Weight, Animals, Humans, Ovum, Chromosome Aberrations, Psychological Tests, Triplets, Mosaicism, Infant, Newborn, Fetofetal Transfusion, Disseminated Intravascular Coagulation, Fetal Diseases, Abnormalities, Severe Teratoid, Karyotyping, Female, Down Syndrome, Pregnancy, Multiple, Gonadotropins, Maternal Age