"I'm a Boy" is a 1966 rock song written by Pete Townshend for the Who.[3] The song was originally intended to be a part of a rock opera called Quads, which was to be set in a future in which parents can choose the sex of their children.
The song is about a family who "order" four girls, but a mistake is made and three girls and one boy are delivered instead. The boy dreams of partaking in sports and other boy-type activities, but his mother forces him to act like his sisters and refuses to believe the truth
That's hard to read as anything but a metaphor for being transmasc