"By birth, mostly. It's in the genes." And normally, Rogue wouldn't really mind telling an Avenger what her mutation was - fight the same fight, right? But considering this was Loki's... well. Considering it was Thor, and how she had already identified herself as Loki's lover, the speculation and conversation was not something she wanted to deal with right now. "An' as for mine... it's complicated. I'd rather not go into it right now."