having uncommonly long ring fingers raises the risk for developing OA of the knee, independent of other risk factors and particularly among women. Index to ring finger length ratio (2D:4D) is a trait known for its sexual differences. Men typically have shorter second than fourth digits; in women, these fingers tend to be about equal in length. Smaller 2D:4D ratios have intriguing hormonal connections, including higher prenatal testosterone levels, lower estrogen concentrations, and higher sperm counts. Reduction in this ratio has also been linked to athletic and sexual prowess.