Ed groaned. "I was already with Sarah when your son first showed up, and when they developed feelings for each other my reaction was to pick as many fights with him as I could to drive him off. It didn't help when I learned he was a homunculus, which are made differently in my Amestris." He grimaced. "They were the purposeful creations of a creature that called himself Father, created humans with a Philosopher's Stone at their core. I wasn't inclined to remember the difference between Ed and them back then."