title: Sex ratio in spina bifida and anencephaly.
mesh_terms: D000483:Alleles; D000757:Anencephaly / Q000235:genetics*; D005260:Female; D005787:Gene Frequency; D005804:Genes, Lethal; D005808:Genes, Recessive; D005838:Genotype; D006801:Humans; D008297:Male; D008954:Models, Biological; D010641:Phenotype; D012730:Sex Chromosomes; D012744:Sex Ratio; D016135:Spinal Dysraphism / Q000235:genetics*