Serum testosterone in neonates predicts the total sperm count of adult males, according to a study published in the Journal of Clinical Endocrinology & Metabolism. Louise Scheutz Henriksen, MD, PhD, and colleagues assessed how reproductive function markers in 3-month-old boys relate with adult reproductive health. They conducted a population-based birth cohort study that included 259 boys examined once around age 3 months and again at age 18-20. They examined mini-pubertal markers of testis function as predictors of adult semen quality using linear regression models. Links between reproductive outcomes in infants and young adults were measured by intra-class correlation coefficients. After evaluating reproductive hormones and semen quality, the study team observed that concentration of serum testosterone in infants was positively linked with total sperm count in adulthood. “Other reproductive hormones and genital measures showed good correlation between infancy and adulthood,” the study authors wrote.