What stats would a human child get?

If you mean child as in non-adult, then it spans a spectrum of child (5-11), pre-adolescent (12-13) and adolescent (14-adult), the stats on each would be different. Normally subtract 2 from 10 for each level below adult and you have sort of a really rough average.

That said, no child PCs on EfU is our policy.

Well than, that being said what is the youngest you would allow a human to be?

15/16 years of age.