The widely used attention-deficit/hyperactivity disorder (ADHD) medication methylphenidate -- best known as Ritalin -- appears to be tied to delayed puberty in male monkeys. But, researchers cautioned that the finding needs to be replicated before parents should concern themselves about similar effects in boys. Male primates given methylphenidate over a 40-month span experienced “impaired testicular descent” and smaller-sized testicles, as well as lower testosterone levels, all of which resolved over the course of the study.
