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Digit ratio (2D:4D) and maternal testosterone-to-estradiol ratio measured in early pregnancy

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Richards, Gareth 
Aydin, Ezra 
Tsompanidis, Alex 
Padaigaitė, Eglė 
Austin, Topun 


jats:titleAbstract</jats:title>jats:pThe ratio of index to ring finger (2D:4D) has been hypothesised to indicate prenatal androgen exposure, yet evidence for its validity is lacking. We report the first pre-registered study to investigate mothers’ early pregnancy sex hormone concentrations in relation to their children’s digit ratios measured at 18–22-month follow-up. Although the testosterone (T) to estradiol (E) ratio correlated negatively with right hand digit ratio (R2D:4D) and directional asymmetry (right-minus-left) in digit ratio (Djats:sub[R−L]</jats:sub>), neither effect remained statistically significant once demographic and obstetric covariates were controlled for. Nevertheless, the multivariate level of analysis did reveal that T correlated positively with left hand digit ratio (L2D:4D) and negatively with Djats:sub[R−L]</jats:sub>. However, the first of these effects is in the opposite direction to that predicted by theory. Taken together, the results of our study suggest research with larger samples is required to determine whether digit ratios are valid proxies for maternal sex hormone exposure.</jats:p>


Funder: NIHR Cambridge Biomedical Research Centre; doi:

Funder: NIHR Brain Injury MedTech Co-operative

Funder: Autism Research Trust

Funder: Simons Foundation Autism Research Initiative; doi:

Funder: Templeton World Charitable Fund

Funder: Medical Research Council; doi:

Funder: NIHR Collaboration for Leadership in Applied Health Research and Care East of England at Cambridgeshire and Peterborough NHS Foundation Trust

Funder: Innovative Medicines Initiative 2 Joint Undertaking under grant agreement No 777394 for the project AIMS-2-TRIALS


Article, /631/136, /692/163, /631/181/2806, article

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Scientific Reports

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Springer Science and Business Media LLC
Wellcome Trust (214322\Z\18\Z)