What If? All in the Family.
It had been a freak accident. Some kind of short-circuit of energy signatures, Dr. Vernard had said when he examined them. The point was that Jon had been dragged here with them from his own facet of reality, and his energy signature was so disrupted that even that dimensional teleporter Mrs. Stark had called in couldn't send him back there. They'd really tried everything, but had finally given up.

And then, there was the other thing.

"So... do you want to tell him?" Vernique asked Svalin as she sat holding her hand on the bed. In Svalin's other hand was the test, clearly positive.