A group of Wisconsin parents are outraged over what could potentially be a transgender athlete participating in a girls’ sport at an area school, according to FOX 11 in Green Bay.

Parents said their daughters started coming home from summer games and practices with welts and bruises that they never noticed on their children before, the outlet reported Wednesday.

Though they declined to specify which sport and which school is involved in the dustup, citing confidentiality concerns, the school in focus belongs to the Green Bay Area Public School District.