For the past few months, Colorado state Rep. Brianna Titone (D) has kept a close eye on the bills neighboring states have been proposing — bills that aim to curb the rights of transgender children from participating in youth sports, accessing bathrooms and getting gender-affirming health care. There’s Arizona, Oklahoma and Utah, which all passed laws barring trans kids — with a focus on girls, in particular — from playing on teams that align with their gender identity. In Kansas, a similar bill passed the state Senate, but was vetoed by Democratic Gov. Laura Kelly. And in Idaho, lawmakers sought...