My kids tend to run on the low side as far as fevers go (which is irritating when I get the looks from the nurses at the ped's office, "why are you bringing him in?" uh, he has an ear infection, trust me. Sometimes I have to go by behavioral symptoms alone. Just happened last week - ds2 was running temps around 100.9 rectal - ear thermometer was more like 99 - sure enough, big fat ear infection. "Mom was right!" gee thanks.).
I haven't read all the posts, but just wanted to point out that there are metabolic influences on temperature, and who knows what else. For example, I think people with some amount of insulin resistance tend to run lower (think basal body temp) but I don't know why.
I might vaguely recall that question in the GDC forms. But it's such a non-specific thing that I can't figure out why it's even worth asking - surely plenty of ND kids run high fevers.