title: Sperm competition and the persistence of genes for male homosexuality.
abstract: Homosexuality is increasingly recognized as having a genetic component. Why then does it persist, when common sense suggests that it should result in fewer offspring? Monozygotic-twin studies permit a rough estimate of the importance of genetics (70%) in the development of male homosexuality, and the proportion of homosexuals remains constant: Fisher's Theorem then tells us there is an advantage to the heterozygote, which we find need be no greater than 2%. Behavior and sperm competition suggest what this advantage might be.
authors.affiliation: Expert-center for Taxonomic Identification, University of Amsterdam, The Netherlands.
authors.forename: F
authors.initials: F
authors.lastname: MacIntyre
authors.forename: K W
authors.initials: KW
authors.lastname: Estep
mesh_terms: D001727:Bisexuality; D005260:Female; D005796:Genes; D005826:Genetics, Medical; D006579:Heterozygote; D006716:Homosexuality; D006801:Humans; D006823:Hybrid Vigor; D008297:Male; D008957:Models, Genetic; D013094:Spermatozoa; D014430:Twins, Monozygotic / Q000235:genetics