Soto BJ, Pereira A, Busch AS, et al. - In this retrospective analysis of a longitudinal population‐based study, researchers sought to describe pubertal progression, growth, genotypes, reproductive hormones, and growth factors in girls with transient thelarche (TT), ie, the appearance, regression and subsequent reappearance of breast buds, vs those who do not present TT (non‐TT). The sample consisted of 508 girls of the Chilean Growth and Obesity cohort. Data reported that 37 girls presented TT and these girls entered puberty by pubarche more frequently (51%) compared with girls with normal progression. Girls with TT below the age of 8 had lower androgens, anti‐Müllerian hormone, luteinizing hormone, and estradiol relative to older girls with TT. No differences in anthropometric variables or FSHB/FSHR genotypes have been detected. TT is a common phenomenon which does not seem to be mediated by hypothalamic‐pituitary‐gonadal axis activation or by adiposity. Hormonal variations between earlier TT and later TT indicate that their mechanisms are different.