Tell your son that the Hawaiian birth certificate, long form, does not even show anyone's religion.
Show him this, a BC from a child born the day after Obama, actually 19 hours later on a weekend, so the form was unlike to have changed in between the births.
Now that's a little hard to read, so here is one from 1963 that has all the same fields. (The '63 copy was made in 1998 and was cropped to only show the copy of the original, and not the copy certification information (Seal, signature, etc) but one can see that the field are the same.)
