In the first few turnings of the Wheel, the Creator was actually involved with the War against his incestous twin sister, the DO. But before the Dragon Reborn could fufill his destiny, the Creator would have him go on a ridiculous quest that took so long that the War was over by the time the DR got back. Finally, in one age, an age long past, an age yet to come, the Dragon Reborn had enough. The DR puffed up his chest, clung to his balls (given the Creator's well known proclivity to balefire the balls off anyone who angered him), and spoketh thus to his Creator:
"Go find your own damn shrubbery!"
Thus the story of why Rand has no balls.