The mismeasure of hands?

Some researchers argue that the ratio between the length of the second and fourth fingers, the 2D:4D ratio, reflects the levels of testosterone and other hormones people were exposed to in the womb. Measuring the ratio, these scientists say, can thus provide insight into the role of hormones in shaping adult attributes such as aggressiveness and sexual orientation. It may also reveal sports prowess and disease risk. But other researchers criticize this work. Ratios are statistically dubious, they contend, and the evidence linking the 2D:4D ratio to prenatal hormone levels is weak. Moreover, they say, the field of 2D:4D research is rife with unrepeatable results.