It was funny because the kid was called "Christopher" for a fair bit before he suddenly became "Nathan".
Oh and that Claremont/Collins back-up story from Classic X-Men is great, super-creepy and very insightful. The original idea was that that was Sinister's TRUE form, and not just him shapeshifting into a child or using a robot. I must say I quite like the Victorian-era scientist origin for Sinister, it still works well while being a bit unoriginal perhaps... but Claremont's original plans for Sinister-as-a-child would have been fun and creepy.