Homosexuality, type 1: an Xq28 phenomenon
1Department of Psychiatry, State University of New York at Stony Brook, New York 11794, USA.
Archives of Sexual Behavior
|April 1, 1995
Summary
This study suggests a gene in the Xq28 region may influence male homosexuality. Maternal relatives of male homosexuals show an unbalanced sex ratio, supporting a genetic link.
Area of Science:
- Genetics
- Human Sexuality
- Behavioral Science
Background:
- X-linked disorders typically show phenotypic manifestations in alternating generations.
- Previous research has explored genetic and environmental factors in sexual orientation.
- The Xq28 chromosomal region has been implicated in studies of male homosexuality.
Purpose of the Study:
- To investigate the potential genetic determination of male homosexuality, specifically Kinsey grades 5 and 6.
- To examine the secondary sex ratio in maternal generations of homosexual probands.
- To explore a genetic hypothesis involving the Xq28 region and maternal inheritance.
Main Methods:
- Analysis of 133 families and 78 kinship groups of homosexual probands.
- Inclusion of 116 families from existing literature, including those of famous homosexuals.
- Statistical analysis of sex ratios among maternal aunts and uncles, and fetal wastage.
Main Results:
- An unbalanced secondary sex ratio was observed in the maternal generation of male homosexuals (uncles to aunts ratio: 241/367, p < 0.0001).
- Fetal wastage in mothers of homosexuals (49%) was comparable to that associated with Xq28-linked semilethal conditions in males.
- A significant deviation in the sex ratio of children born to female carriers of Xq28-linked conditions (1,232/1,062, p ≤ 0.0001) was noted.
Conclusions:
- The findings support a genetic hypothesis for a major type of male homosexuality, potentially linked to the Xq28 region.
- Maternal genetic influence, with mothers acting as carriers, is suggested as a significant factor.
- Additional evidence includes increased instances of infertility, pregnancy loss, and specific social traits among maternal relatives.
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