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Abstract
The Darwinian paradox of male homosexuality in humans is examined, i.e. if male homosexuality
has a genetic component and homosexuals reproduce less than heterosexuals, then why
is this trait maintained in the population? In a sample of 98 homosexual and 100 heterosexual
men and their relatives (a total of over 4600 individuals), we found that female maternal
relatives of homosexuals have higher fecundity than female maternal relatives of heterosexuals
and that this difference is not found in female paternal relatives. The study confirms
previous reports, in particular that homosexuals have more maternal than paternal
male homosexual relatives, that homosexual males are more often later-born than first-born
and that they have more older brothers than older sisters. We discuss the findings
and their implications for current research on male homosexuality.