The Ancestor 2

The great war that had killed a quarter of Earth's population had come to an end. The Derkadans focused on dismantling the remnants of the theocracy that had oppressed them for centuries and caused the deaths of three hundred million people. To ensure that the peace would last, the Eyan leadership approved a plan to reduce the maximum testosterone levels of all men, hoping the measure would lessen the aggression of their sex.
Once the Derkadan leadership also agreed, the plan was implemented on a global scale. Despite countless tests, something went terribly wrong. A race against time for the future of humanity had begun.