The ratio of the lengths of the index finger to the ring
finger in 46 males and the number of CAG repeats for
each.
Arguments
source
inferred from Manning, J.T., P.E. Bundred, D.J.
Newton, and B.F. Flanagan. 2003. The second to fourth
digit ratio and variation in the androgen receptor gene.
Evolution and Human Behavior 24: 399-405.