Genome-wide scan demonstrates significant linkage for male sexual orientation

Area of Science:

• Genetics
• Human Sexuality
• Behavioral Science

Background:

• Family and twin studies suggest a genetic basis for male sexual orientation.
• Previous research on genetic linkage to sexual orientation has produced conflicting results, particularly concerning chromosome Xq28.

Purpose of the Study:

• To investigate the genetic underpinnings of male sexual orientation.
• To identify specific chromosomal regions associated with the development of sexual orientation in men.

Main Methods:

• A genome-wide linkage scan was performed on 409 independent pairs of homosexual brothers, involving 908 individuals across 384 families.
• This represents the largest study of its kind to date, enhancing statistical power.

Main Results:

• Two chromosomal regions showed significant linkage: the pericentromeric region of chromosome 8 and the Xq28 region.
• Linkage on chromosome 8 (maximum two-point LOD = 4.08) overlaps with a previously identified region.
• Linkage at Xq28 (maximum two-point LOD = 2.99) is consistent with prior research findings.

Conclusions:

• The findings support the role of genes located on pericentromeric chromosome 8 and chromosome Xq28 in the development of male sexual orientation.
• These results, considered alongside previous studies, strengthen the evidence for specific genetic influences.