BackgroundAnogenital distance (AGD), a sexually dimorphic measure of genital development, is a marker for endocrine disruption in animal studies and may be shorter in infant males with genital anomalies. Given the correlation between anogenital distance and genital development, we sought to determine if anogenital distance varied in fertile compared to infertile adult men.MethodsA cross sectional study of consecutive men being evaluated for infertility and men with proven fertility was recruited from an andrology clinic. Anogenital distance (the distance from the posterior aspect of the scrotum to the anal verge) and penile length (PL) were measured using digital calipers. ANOVA and linear regression were used to determine correlations between AGD, fatherhood status, and semen analysis parameters (sperm density, motility, and total motile sperm count).FindingsA total of 117 infertile men (mean age: 35.3±17.4) and 56 fertile men (mean age: 44.8±9.7) were recruited. The infertile men possessed significantly shorter mean AGD and PL compared to the fertile controls (AGD: 31.8 vs 44.6 mm, PL: 107.1 vs 119.5 mm, p<0.01). The difference in AGD persisted even after accounting for ethnic and anthropomorphic differences. In addition to fatherhood, on both unadjusted and adjusted linear regression, AGD was significantly correlated with sperm density and total motile sperm count. After adjusting for demographic and reproductive variables, for each 1 cm increase in a man's AGD, the sperm density increases by 4.3 million sperm per mL (95% CI 0.53, 8.09, p = 0.03) and the total motile sperm count increases by 6.0 million sperm (95% CI 1.34, 10.58, p = 0.01). On adjusted analyses, no correlation was seen between penile length and semen parameters.ConclusionA longer anogenital distance is associated with fatherhood and may predict normal male reproductive potential. Thus, AGD may provide a novel metric to assess reproductive potential in men.

Anogenital distance may provide a novel metric to assess testicular function in men. Assuming that anogenital distance at birth predicts adult anogenital distance, our findings suggest a fetal origin for adult testicular function.

Infertility in men is a common condition. At the core of the medical evaluation of the male partner in a couple who are unable to conceive is the history and physical examination. Special attention should be directed to the patient’s developmental history and any use of testosterone products. The physical examination focuses on the genitals, and includes assessments of the size and consistency of the testicles, epididymis, vas deferens, and presence of varicoceles. Although many sophisticated tests are available, semen analysis is still the most important diagnostic tool used to assess fertility, and includes parameters such as sperm count, motility and viability. Treatment of male factor infertility can involve targeted agents, in the case of specific conditions such as hypogonadotropic hypogonadism, or it can be empirical—using medical therapy or assisted conception techniques—for patients in whom no underlying cause has been identified. Although an all-encompassing treatment for male factor infertility has not yet been developed, the field offers many promising avenues of research.

Anogenital distance (AGD) is a marker for endocrine disruption in animal studies in which decreased male AGD has been associated with testicular dysfunction. The objective of the study was to investigate whether anogenital distance could distinguish men with obstructive azoospermia (OA) from those with nonobstructive azoospermia (NOA). To accomplish this, azoospermic men were recruited and evaluated at a men's reproductive health clinic in Houston, TX. Anogenital distance (the distance from the posterior aspect of the scrotum to the anal verge) and penile length (PL) were measured using digital calipers. Testis size was estimated by physical examination. Logistic regression was used to compare AGD lengths in men with OA and men with NOA. A total of 69 OA men (mean age: 44.2 ± 9.2) and 29 NOA men (mean age: 32.8 ± 4.8) were recruited. The NOA men possessed significantly shorter mean AGD than the men with OA (AGD: 36.3 vs. 41.9 mm, p = 0.01). An AGD of less than 30 mm, had a 91% specificity in accurately classifying NOA. Moreover, after adjustment for age, race, and BMI, an AGD of less than 30 mm yielded a significantly increased odds of NOA compared to OA (OR 5.6, 95% CI 1.0, 30.7). In summary, AGD may provide a novel metric for assessing testicular function in men and in distinguishing OA from NOA.

Obese patients have a lower prevalence of varicoceles detected by ultrasound. The lower prevalence is independent of physical examination and more likely due to another factor.