Gender diagnosticity and androgen receptor gene CAG repeat sequence

Area of Science:

• Behavioral genetics
• Psychological sex differences
• Human genetics

Background:

• Psychological masculinity-femininity is assessed using the gender diagnosticity (GD) approach.
• The androgen receptor (AR) gene on the X chromosome is implicated in sex-typed behaviors.
• Previous research suggests a potential genetic basis for sex-typed psychological traits.

Purpose of the Study:

• To investigate the relationship between psychological masculinity-femininity and CAG repeat length in the androgen receptor (AR) gene.
• To examine this relationship in adult and adolescent samples across different countries.
• To utilize twin comparisons to explore genetic and environmental influences.

Main Methods:

• Employed the gender diagnosticity (GD) approach to measure psychological masculinity-femininity.
• Analyzed the length of CAG repeat sequences in the X-linked androgen receptor (AR) gene.
• Utilized adult samples from Australia and Sweden, and adolescent twin data from Australia.
• Conducted within-pair comparisons in dizygotic (DZ) and monozygotic (MZ) twins.

Main Results:

• A weak, statistically significant correlation (r = .11 to .14) was observed between GD scores and AR CAG repeat length in adult samples.
• This weak relationship was not replicated in adolescent samples, particularly in males.
• Twin analyses did not support a significant genetic influence of AR CAG repeat length on GD scores.

Conclusions:

• The relationship between AR gene CAG repeat length and psychological masculinity-femininity is weak in adults and not evident in adolescents.
• Genetic factors, specifically AR CAG repeat length, may play a limited role in sex-typed psychological dimensions.
• Larger sample sizes and longitudinal data are needed to further clarify these complex genetic-behavioral relationships.