Through a glass, darkly: Human digit ratios reflect prenatal androgens, imperfectly.
Level 5 - mechanism / opinion, no new human data
Narrative review synthesizing existing literature without systematic review methodology or primary data
PubMed 32014464 · doi:10.1016/j.yhbeh.2020.104686
What was done
Narrative review examining evidence on whether right-hand second-to-fourth digit ratios (2D:4D) reflect prenatal androgen exposure, explain male-female differences, and differ by sexual orientation in women.
What was found
The abstract provides no quantitative values or effect sizes. It notes that right-hand 2D:4D is on average higher in women than in men, and that meta-analyses confirm lesbians have, on average, lower (more masculine) 2D:4D ratios than heterosexual women, supporting a role for prenatal androgens in female sexual orientation at a group level.
Why it matters
It highlights prenatal androgen exposure as a developmental factor in adult sexual attraction while establishing that 2D:4D is an imperfect proxy that cannot be used to determine an individual's sexual orientation.
Limits
This is a narrative review providing no primary data or specific statistical figures in the abstract. 2D:4D is an indirect proxy for fetal hormone exposure, and substantial within-group variability precludes individual-level predictive validity.
Cited by
- supports Marc Breedlove's original 2000 study on digit ratios and sexual orientation found no significant difference in 2D:4D finger length ratios between gay men and heterosexual men.