Overview
- The meta-analysis in Frontiers in Psychology combined data from 51 studies and 227,648 people, incorporating unpublished datasets to address publication bias.
- Exclusively homosexual men tended to have higher, more female-typical 2D:4D ratios, while exclusively homosexual women tended to have lower, more male-typical ratios.
- Digit ratios among bisexual men and women were closer to those of heterosexual participants, indicating that grouping bisexuals with homosexuals can mask differences.
- Findings were stronger in studies using photocopies or digital scans of hands, with weaker results when participants measured their own fingers.
- The authors describe the effects as small and the 2D:4D measure as an imperfect proxy for prenatal hormones, cautioning that it is not diagnostic at the individual level.