Gaml-Sørensen A, Brix N, Ernst A, et al. - Researchers examined if and how prenatal exposure to antibiotics influence the timing of pubertal development in sons and daughters. In this population-based cohort study a sample of 15,638 children born 2000–2003 in Denmark was included. They followed up the children half-yearly from 11 years of age and throughout sexual maturation yielding information on Tanner stages, acne and axillary hair, in addition to voice break and first ejaculation in sons and menarche in daughters. Maternal antibiotic use in pregnancy was reported in 21.1%. Both prenatal exposure to antibiotics at any time in pregnancy and trimester-specific prenatal exposure to antibiotics and pubertal timing were investigated, adjusting for maternal baseline socioeconomic and lifestyle characteristics. Further, in a sub-analysis, they employed an active comparator approach with restriction to women reporting to have a urinary tract infection (cystitis) treated with either penicillin or sulfonamides. Outcomes revealed no correlation of prenatal exposure to antibiotics with pubertal timing. Similar results were observed in both the trimester-specific analyses and the active comparator analysis.