Finger Length Ratio

Your result, the one DNA position behind it, and what the research says.

8/10 confidence.

About Finger Length Ratio

Hold your hand up and compare the index finger with the ring finger. In most people the ring finger is a little longer, and the size of that difference - written as the 2D:4D ratio - varies between people and between the two hands. It has been studied so much because of a long-standing idea that it records hormone exposure before birth, an idea both of the studies on this card question. The ratio measured in fetuses is lower than in children and adults and rises slightly through childhood, so what stays fairly steady is where a person sits in the range rather than the number itself. This position sits inside LIN28B, in a non-coding stretch of the gene that helps set the timing of growth and puberty, and it is one of the few places in the genome linked to the ratio in large samples.

Good to know: Your position relative to other people is largely set early and changes little, although the ratio itself rises slightly through childhood. Your two hands often differ more from each other than genotypes differ on average. Claims linking this ratio to personality or ability are contested and are not made here.

Fun fact: The index-to-ring finger ratio differs on average between men and women, although the two ranges overlap so much that one hand tells you little, and the size of the gap depends on which hand is measured and how.

Discovery: Common variants affecting the 2D:4D ratio were mapped in genome-wide studies.

The Variant

The single variant behind this trait

Gene: LIN28B

Variant (rsID): rs314277

Location: Chr 6:104,959,787

dbSNP rs314277

The studies

A variant in LIN28B is associated with 2D:4D finger-length ratio, a putative retrospective biomarker of prenatal testosterone exposure (Medland SE et al., American journal of human genetics, 2010)

Genome-wide association study identifies nine novel loci for 2D:4D finger ratio, a putative retrospective biomarker of testosterone exposure in utero (Warrington NM et al., Human molecular genetics, 2018)

Other lifestyle traits

Facial Profile: A change near the master gene for bone formation, linked to the vertical proportions of the face.

Sensitivity to Chewing Sounds: A variant near the TENM2 gene, weakly associated with finding the sound of other people chewing unusually irritating.

Earlobe Size: A variant on chromosome 1 linked in a large study to whether the earlobe hangs free or is joined to the head, and in one much smaller study to lobe size.

Back to All Traits

Content updated September 2026.

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