A three-year-old girl was triggered to enter precocious puberty following exposure to her trans-identified father’s “gender affirming” topical estrogen gel. The toddler was seen by pediatric endocrinologists after experiencing breast development and vaginal discharge over a time frame of six months. The father, a male who identifies as a “woman,” told clinicians that he was having daily skin-to-skin contact with the toddler girl, despite his daily application of estradiol gel 3.75mg to his chest, abdomen, shoulders, and thighs. He had previously been using an estradiol spray on his forearms only. A case study, first published in the European Society for...