Ty again saw in his mind's eye the person his newly fertilized self would be as he became a xygote in response to the sperm fertilizing him and started to lodge into his new mother's womb. But what he saw surprised him. Immaculately applied makeup that emphasized his eyelashes and lips. Valuable jewelry made of gold and precious stones. Soft fabric which left much of his skin uncovered. Shoes which elevated his heels upwards and added emphasis to his steps.
It slowly dawned on him, as the king and queen's heir he would not be a prince. She would be a princess.
Some force outside of him, perhaps the thrall of the second X chromosome that had fertilized him, swiftly convinced him to cast off his antipathy. Getting to be of royal blood was far more important than manhood, it reminded him.
As she gestated, his self-perception altered- he watched himself turn from the commoner boy he had been before regression to the princess she would be shortly. His figure subtly shrank down all over, and his skin smoothed. He felt his proportions alter so his shoulders drew inwards, his hips pushed outwards and his muscles and limbs turned lithe. His face altered to have softer features and more pronounced lips while his hair lengthened substantially. All of this felt right, as he realised beauty was coming into his possession. Once he was she, it would be hers to keep.
Now came the parts of the change that made he, she. The undeveloped nipples on his chest had their formation filled in by the X chromosome he had gained, growing as breasts formed under them- now he had mammaries with which to feed her own heir, and in the meantime with which to attract a male and from which she could experience pleasure unlike any a man could.
Barely noticing how his mind had already started to adopt to her new gender, he looked past her new chest to his penis, the part of him he most associated with manhood. Fittingly, the phallus now started to change, and with it connection to his old gender was slowly severed. The shaft which had been able to fill others with his seed receded and its nerve endings bundled up tighter and tighter as it turned into her clitoris. The testicles which contained his seed pulled up into the body and reshaped into ovaries, and for a moment he felt castrated- but then she embraced her new self. He turned to she, male turned to female, man turned to woman. And Ty now felt able to describe herself as a princess. The sense of newfound femininity was exacerbated by Ty's scrotum forming a slit down its centre and becoming her vagina.
Now she had turned into the princess she would be when she was born in her mind, she looked down at her xygote self and wondered who she would be...