title: The origin of "X cells" of the human placenta and their possible relationship to intrauterine growth retardation: an enigma.
mesh_terms: D005260:Female; D005315:Fetal Diseases / Q000209:etiology*; D005865:Gestational Age; D006130:Growth Disorders / Q000209:etiology*; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D008856:Microscopy, Fluorescence; D010920:Placenta / Q000166:cytology*; D010922:Placenta Diseases / Q000209:etiology; D011247:Pregnancy; D011296:Prenatal Diagnosis; D012737:Sex Factors