I was never given an editorial edict and I’m glad. It’s not a story I would have liked to attempt for a number of reasons. Its undoubtedly a novel idea to have a female (Mystique) father a child but I’d prefer to see a new character created to fit the role of offspring—Or use a character readers would never anticipate as Mystique’s child. Why should a blue skinned character be parent to another blue skinned character? I’m not a fan of the incestuous soap opera approach of using tenuous links to tie up every loose end, in a limited group, with an ever more intricate tangle of relationships.
Another consideration is how the introduction of a parent affects a character. The uncertainty of Nightcrawler’s past contributes to the tragedy of his character and situation. I wouldn’t want to risk spoiling those fundamentals unless there was a really big pay-off created by exploring the familial bond. I favour the tradition of creating new storylines and characters rather than tying all the existing threads into a knot.
For instance, Kurt’s father might be a product of Nazi eugenics (or a religious fanatic) who, having disposed of Kurt’s infant body shortly after birth, would be so enraged to discover this insult to his genetic lineage survived he would set out to destroy him.
Alternately, his mother might be a normal (non-mutant) woman (with a family) who had been told Kurt was still born to spare her the knowledge of Kurt’s true nature—
-- Confronted by Kurt she screams in terror and he flees heartbroken
-- She accepts Kurt, seeing the man within, but his siblings (who might also be mutants) turn on him.
These are notions off the top of my head and I don’t suggest I would have used them or believed they could survive serious development. But they do offer Kurt his own unique back-story rather than making him a appendix to Mystique’s.