Anogenital distance as a measure of human male fertility

In humans, recent studies have correlated anogenital distance (AGD) in adult men to testicular function. While studies of a group of men suggest an association, the utility of AGD in an infertility evaluation remains uncertain. We sought to determine the utility of AGD to predict male fertility.

Between 2010 and 2011, men were recruited at a urology clinic to participate. AGD was measured using digital calipers in men being evaluated at a urology clinic. ANOVA and ROC analyses were used to determine correlations between AGD, fatherhood status, and semen parameters.

In all, 473 men were included in the analysis with a mean age of 43 ± 13 years. Anogenital distance was significantly longer in men with higher sperm concentration, total sperm count, and total motile sperm count. In order to evaluate the discriminating ability of AGD, ROC curves were created comparing AGD and total testis volume. The area under the curve (AUC) was significantly larger for total testis volume compared to AGD when evaluating fertility (0.71 vs 0.63, p = 0.02). Similarly, there was a trend towards a higher AUC for testis volume compared to AGD for sperm concentration and total sperm count. Stratification of men with long/short AGD and large/small testes also did not improve the predictive value of AGD.

While AGD is associated with sperm production on a population level, at the individual level the distinction based AGD alone cannot accurately estimate the efficiency of spermatogenesis.