To the editor: We read with great interest a meta-analysis by Maleki et al. [1] on the association between prenatal excess of androgen exposure in the offspring of mothers with polycystic ovary syndrome (PCOS) and risk of attention-deficit/hyperactivity disorder (ADHD) in them. They found that maternal PCOS increases the offspring risk of ADHD. However, we have to point out a deficiency of this study, we noted that 1 of 6 articles that were included in this study did not meet the eligibility criteria as it’s object was different [2]. Hergüner et al. [2] aimed to compare ADHD symptoms between women with PCOS and controls. This deficiency may introduce bias and lead to a false conclusion.