title: Why two sexes? Sex determination in multicellular organisms and protistan mating types.
authors.forename: Eric S
authors.initials: ES
authors.lastname: Haag
mesh_terms: D000818:Animals; D012734:Disorders of Sex Development; D056890:Eukaryota / Q000235:genetics / Q000502:physiology*; D005260:Female; D007448:Invertebrates / Q000502:physiology*; D008297:Male; D019849:Sex Determination Processes