Jacob thought of a different thing he could try. Making the human race a different species would be kinda cool, but would also cause a lot of upheaval. Instead, maybe he could try reversing everyone's gender? He had always felt like it was weird how men and women were treated so differently considering all it really signified was what kind of sperm you came from. He quickly saved the existing world as a separate file, and then used the game to scan the whole world. He then found the part of the stats that showed people's sexes, and changed Male to Female and Female to Male, before clicking Save.
Unlike the small changes Jacob had made before, this one took a little while, but he got to watch as it spread all over the world, transforming every person. The screen showed millions of people from all over the world, their clothes vanishing so Jacob could see their whole bodies, get changed by the wish.
Males had their figures turned curvaceous and soft, their chests swelled up as they developed breasts, their penises shrank down into sensitive clitorises, and their testicles pulled up inside them to form ovaries that joined up with a womb while their scrotums unfurled into vaginas.
Females had their figures turned narrow and firm, their breasts receded into pectoral muscles, their vaginas sealed up into sacs, their ovaries moved down into the new sac and became their testicles, and their clitorises lengthened and thickened to form penises.
After seeing a lot of people change, Jacob noticed his own clothes vanish, and an indescribable sensation washed over him as he too was reshaped by the game. He hadn't used it on himself before, and was finding out it felt irrepressible. It melded him to its will, seeming to reach back to his conception and turn the Y chromosome which he had had to an X, and knew that he would not be male anymore- now she would be female.
His body followed the program's instructions, and he felt it start to emasculate him. His figure reshaped to feminine proportions, and grew and shrank as it guided him to. His chest developed in response to the hormones instilled in his altered conception, and mammary glands and breasts developed while his nipples grew large and sensitive. He saw his facial features alter to look more girlish in his reflection. Even his sexuality was altering- all of a sudden he felt more desire towards penises than vaginas.
As if in response to this, his body's castration took place. His penis rapidly shrank away, and he felt two lumps move up inside his body and seem to reconstitute. Now he would not have testicles full of sperm to fertilize women- she would have ovaries containing eggs to be fertilized by men. She felt more right than he now, she realized, as her scrotum tucked inwards and a slit formed down its centre, a moist passage extending inside her as her vagina fully formed.
Once the weird sensation of getting reshaped by the game finished, Jacob looked at herself in astonishment. She looked indistinguishable from someone who had been born female, and from looking at the footage on the laptop, it seemed like the rest of the former men in the world were now too. She wondered what to do next...