Ty decided to try indulging something he'd wondered about for as long as he could remember. What if he'd been born a girl instead of a boy? He felt like maybe it'd fit him more, as he'd always been a pretty scrawny, sissy boy, and had quietly begun to wonder about his sexuality.
As he made the wish, for him to have been born a girl instead of a boy, he pictured something. An ovum, surrounded by greedy sperm all eating away at its outer walls, desperate to fertilize it. Ty could tell one was about to fertilize it, and sensed the Y chromosome it contained- and before it could, another sperm with an X chromosome hastened all of a sudden and bore inside first.
Ty gasped as the vision faded, and realized he'd altered both his history and his body. Not that 'his' would be the right term now. He felt a tingling sensation spread through him, and pulled off all his clothes, standing naked in front of the mirror on his closet door. And with amazement, he watched as she started to transform from male to female.
All through the teen's body, the abundant testosterone was turning itself into estrogen, filling it with unfamiliar arousal somehow stronger still than he had experienced when male puberty had kicked in. He breathed heavily and noticed his breaths heighten in pitch. His facial structure softened, and his lips grew puffier. His hair lengthened down his back, and his neck narrowed with the bulge in his throat vanishing.
He felt his shoulders and torso narrow and his hips widen, altering his proportions to make him even less boylike, and his arm and leg muscles clenched tightly and became more lithe and petite. His hands and feet shrank with them, more eloquent and dainty like this. His skin turned smoother and more supple to the touch, and his butt filled out and rounded around his wider hips.
A whimper escaped Ty's lips as the changes surrounded his chest- the development his masculine hormones had stifled was now catching up in full force. He saw his nipples expand and grow sensitive, getting erect with the hormones surging through him, and with each deep, pleasured breath Ty saw himself sprout. Breasts, she was forming breasts. He imagined having them rubbed, pinched, licked, sucked. Her lovers would pleasure them and her babies would feed from them.
Babies... Ty stared down past her tits to his hard penis. He could tell he wasn't a man anymore from how disconnected he felt from it. And sure enough, it hastily began to recede. Inch after inch his phallus shrank away, and his testicles clenched up and with two wet pops moved up inside the body. They linked to a womb which formed in Ty's crotch and reshaped themselves into ovaries.
As it formed, Ty's connection to this new life finalized. The words he used to describe himself altered. Ty...ra. S...he. Fe...male. Wo...man. Seeing his penis finish receding into a tiny sensitive nub and form her clitoris, and his scrotum unseal itself and form her vagina, made it undeniable.
Tyra stared at her girl's body in amazement. She could tell her wish had made it so everyone would remember her as a girl, and she remembered her life as a girl even knowing she had just wished it into existence. It amazed her to think this was her life now.