Ty realized that what struck him as an even hotter concept than the virus spreading was for it to affect everyone at the same time. Everybody would share the same experience simultaneously, experience the same ecstasy (though of course for people not old enough to experience puberty it wouldn't be sexual), get to recognize the feelings of both sexes as they gave up their old one and embraced their new one. And he wanted to see it, see its effect on people's bodies, get a sort of omniscient view of how people changed all over the world.
His wish was granted, and the entire world seemed to freeze. Everyone, including Ty, was suddenly motionless and naked, as inside every human's body the virus emerged, latched onto the hormones that control the body's sex and inverted them. Not only Ty, but everyone in the world felt transfixed by the feeling, as if their bodies and minds had been opened to a new world.
Ty saw people of every age and colour and country as they were reshaped by the virus. 3.9 billion boys and men all had their manhood receded away, while 3.9 billion girls and women had their womanhood sealed up. Firm masculine bodies slimmed and softened into curvy feminine bodies, and vice versa. Half the world formed mammaries and large soft breasts, and half the world had their bosoms shrink into muscular pectorals. And at last the reproductive parts of every human shifted, as 3.9 billion people's testicles moved inside them to connect with a womb and moist slits formed where their manhood had been, while 3.9 billion people's ovaries moved into a sac between their legs and phalluses grew above them.
The virus had made every male body become female and every female body become male, and even though the changes had ended most people were transfixed. Even boys were stunned by the realization that they were now girls, and girls by the realization that they were now boys. Adults were a little more than just stunned thanks to the inrush of unfamiliar hormones from their newly transformed bodies. Primal reproductive urges were overpowering all else, and practically every fertile person was seeking out any other fertile person in a haze of lust.
Ty felt it too, and wondered whether to find a newly-transformed person to breed her, or to watch some people doing so with her new omniscience...