"No! Make it stop!" Josh whimpered. By now, his voice sounded completely feminine. Glancing down, he was dismayed to find his body structure had changed already, leaving him girlishly slender with wider hips. He could only guess what his face looked like.
"Don't worry, honey," his Mom soothed. "It's nearly finished. Oh, you're already so pretty! Isn't she, Bridget?"
Josh's sister nodded. "Very pretty. I know the boys are going to love her."
"Stop calling me a 'her!'" Josh yelled, once more trying to struggle. He could feel a heat building up as his hair grew long. "I'm still a man! You can't make me a-AAAH!"
His protests turned to cries of pleasure as his erection finally erupted, shooting out his last act of male defiance. His sister's friends shrieked and giggled as a bit splashed on them, but they did not get off his legs. Instead, they along with the others watched enraptured as Josh's spent manhood retracted into a tight opening now forming in its place.
"Welcome to womanhood, Josh," his, now her, sister said cheerfully. "Is she getting a womb now?"
"Technically, her uterus and birth canal were complete already," the Asian woman explained, checking off something on her papers. "No doubt her feelings of pleasure are through the roof right now while the nanites do a bit of neural rewiring to ease her transition. Oh, and here comes the last bit."
Sure enough, Josh arched her back and gave out a loud moan as her chest bloomed into a healthy pair of breasts. Rapidly they grew until they reached a large perky size that would look quite eye-catching in the right outfit. She would have protested if it did not feel so good.
"Oh, I see she's gifted with my family's genes just like her sister," Josh's mom noted with delight.
Instantly, the newly made girl relaxed, panting in exhaustion even though she had only woken up a few minutes ago. Despite knowing that she ought to be crying in horror, she simply lay there with a bemused smile as her limbs were finally released.
"And there," the Asian woman declared with a nod. "The changes are complete, and the nanites are purged. Congratulations, Mrs. Jacobson. You now have a healthy, beautiful daughter. Have you chosen a name?"
"Yes. I've always liked the name Kathryn. Kathryn Joy Jacobson. We'll call her Kathy."
The woman filled out the appropriate space in her form. "Done. Just sign here, please."
Kathy, formerly Josh, let her eyes drift close. Distantly, she could feel her sister's friends arranging her body into a more comfortable position before covering her with a blanket. Well, how considerate. Then, she fell into an exhausted sleep.