Erik is leader of the world and has children born through a breeding program. Erik becomes curious in who is the "mother" of his children, only to find out the "mother" is male and has been send away because he has become useless(?). The "mother" is Charles and Erik learns that Charles was the first (unwilling) subject in this breeding program. Erik recuse Charles, and falls in love with him (don't remember if Charles returns Erik's feelings, all I know there was lots of angst after Charles was saved)

-thank you, if someone finds it