The Psychobiology of Sex Orientation 2nd ed. The former proposes that SSB could persist in the population if genes for this behavior confer a harmonizing reproductive advantage in individuals only possessing one copy of the gene, or heterozygotes, as opposed to those in possession of two homozygotes. The perceived causes of sexual orientation have a significant bearing on the status of sexual minorities in the eyes of social conservatives. The final stage of the investigation involved performing experimental crosses of flies from both of these identified lines and examining the resulting offspring. In some cases though, it appears that this switching off can occur in a non-random fashion. Without the gene, the mice exhibited masculine sexual behavior and attraction toward urine of other female mice.
Women have two X chromosomes, one of which is "switched off".
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The inactivation of the X chromosome occurs randomly throughout the embryo, resulting in cells that are mosaic with respect to which chromosome is active. The evolutionary advantage of homosexuality: Sickle-cell anemia is caused by a mutation that greatly reduces the oxygen-carry capacity of hemoglobin, our chief oxygen-carrying protein in red blood cells. Personality and Social Psychology Bulletin. In the full sample they did not find linkage to Xq A conceptual analysis and quantitative review". While scientists do not know the exact cause of sexual orientationthey theorize that a combination of genetic, hormonal, and social factors determine it.
Also, the authors of the study acknowledge that a large number of sexual partners may not lead to greater reproductive success, specifically noting there is an "absence of evidence relating the number of sexual partners and actual reproductive success, either in the present or in our evolutionary past". This idea makes the paradox of homosexuality, which we will define as a sexual preference for same-sex partners, particularly pronounced because it fundamentally violates a core principle of evolution: That it makes absolutely no evolutionary sense. Granted, it is tempting to conclude that the persistence of homosexual behaviour in the animal kingdom offers proof that this behaviour confers some kind of benefit. Sexual orientations Asexual Bisexual Heterosexual Homosexual. There is no 'cure' for homosexuality because it is not a disease. European Journal of Epidemiology.