title: Observations on the epidemiology of simple hypospadias.
abstract: A descriptive epidemiological study of simple hypospadias-that is, hypospadias without coexisting malformation outside the genital system-in a birth population of 46,927 singleton males and 1,013 twin males showed that the condition was significantly more common (P < 0.001) in uniovular twin males than in either singleton or binovular twin males. Also the temporal distribution of dates of conception had a significant cyclic pattern for each year of the study. Both observations are thought to support the view that gonadotrophin levels at stage 3 sexual organogenesis play an important part in normal masculinization of male external genitalia.
mesh_terms: D006063:Chorionic Gonadotropin / Q000097:blood; D004200:Diseases in Twins; D005260:Female; D005262:Feminization / Q000209:etiology; D005837:Genitalia, Male / Q000254:growth & development; D006801:Humans; D007021:Hypospadias / Q000453:epidemiology* / Q000209:etiology; D007231:Infant, Newborn; D008297:Male; D010902:Pituitary Gland / Q000378:metabolism; D010920:Placenta / Q000378:metabolism; D011247:Pregnancy; D012621:Seasons; D013997:Time Factors
chemical_list: D006063:Chorionic Gonadotropin