title: No association between two candidate markers of prenatal sex hormones: digit ratios (2D:4D and other) and finger-ridge counts.
abstract: The second-to-fourth digit ratio (2D:4D), putatively indexing prenatal androgen levels retrospectively, has become increasingly popular as an easily applied measure in research into the prenatal sex-hormonal bases of behavior, health, and disease. However, its validity has not yet been conclusively demonstrated and in fact is currently debated, because validation tests of 2D:4D with other, prenatally established, presumed markers for prenatal sex-hormone action have yielded mixed evidence or still are unavailable. Hence, the associations of 2D:4D with finger-ridge counts, one such further under-researched marker, were examined in this study. In a sample of 75 male and 75 female normal healthy adults, the six possible finger-length ratios of the human hand (from 2D:3D to 4D:5D, including the classic 2D:4D ratio) were ascertained with two commonly used measurement methods (imaged-based vs. fingers measured directly), along with two traditional dermatoglyphic traits (total and absolute finger-ridge counts). Sex differences in finger-length ratios (lower in men) generally were of moderate size (about .5 SD units), whereas those in finger-ridge counts (higher in men) were small to negligible (about .2 SD units). Within-sex analysis did not indicate theory compliant (i.e., negative) correlations between these two sets of traits that were consistent, noteworthy, or reliable. Finger-length ratios and finger-ridge counts are ontogenetically overlapping in their prenatal formation and anatomically adjacent. Hence, possible temporal and localized sex-hormonal effects in prenatal life are unlikely to account for their nonassociation. The current findings cast some doubt on the validity of these retrospective pointers to prenatal androgen levels.
authors.affiliation: Department of Basic Psychological Research, School of Psychology, University of Vienna, Liebiggasse 5, Vienna, Austria.
authors.forename: Stefan G
authors.initials: SG
authors.lastname: Dressler
authors.forename: Martin
authors.initials: M
authors.lastname: Voracek
mesh_terms: D000328:Adult; D003878:Dermatoglyphics; D005260:Female; D005333:Fetus / Q000502:physiology; D005385:Fingers / Q000033:anatomy & histology*; D012739:Gonadal Steroid Hormones / Q000502:physiology*; D006801:Humans; D008297:Male; D012727:Sex Characteristics; D055815:Young Adult
chemical_list: D012739:Gonadal Steroid Hormones