Magnus nods at the sensibility in Loki's words. He has always been considered something of an intellectual...not on a level with Beast, Reed Richards, or any of the dozens of other superminds on his homeworld, but smart enough to understand most of what he learns and wise enough to know who to ask when his own intellect fails him.
So when Loki mentions the foolishness of ignoring an avenue of learning for the sake of proving one has a phallus, Erik shakes his head.
"I could not have put it better myself."
Then the question comes about 'magical potential in his family,' and Erik's rueful smile evaporates, a shadow crossing over his eyes.
"...not exclusively, but yes, there is a trace of magical potential in my bloodline...or rather, in my daughter's."
Red sigils, swirling through the air in patterns of light. Eyes that go from a deep forest green like her mother's to a burning, hellish crimson. A mouth, twisted into a rictus of a wicked grin on one occasion, then shattered and slack with grief on another, much later one, and three words that, once uttered, destroyed Magneto's dreams forever.
"No More Mutants."
"As a child, she and her brother were adopted by a family of gypsies...I did not become aware of their existence until they were fully grown and well into their abilities. The family's resident fortuneteller, one Agatha Harkness, discovered Wanda's gift to manipulate the laws of probability, and used it to teach her chaos-magick...a power old enough to rival even Asgard. Had their training not been interrupted by the angry mob I rescued my children from, I have little doubt Harkness would have exposed my daughter to the Darkhold...the very book of chaos itself. She, you see, derived her powers from Cthon, the demonic author of that book."
His hand trembling, Erik wipes his face, which has become a shade paler than usual and beaded with sweat.