My dd just has "artists' blood" in her from BOTH sides of the family, so she's been drawing and tracing letters ever since she could hold one correctly, at about age 2.
She's 5 now, and in pre-school, and it wasn't until just before she got to sign all her Valentine's Day Cards this year that she really got the CORRECT spelling of her name. (We practiced alot, because she's so independant and wanted to do them herself!!)
Occasionally, she'd switch around the "s" and "o" in her name...Madison, but now she spells it right 100% of the time. And this seemed to happen overnight.
So in my case, even though a child may seem to have "the artists' gene", still doesn't predict at what age they will be able to spell their name correctly.
I'm sure your son will come around in due time, and one day you may be having to wipe (or paint over, as I've had to do) his name off your walls, floors, etc...

But...at least he'll be writing his name! Right?
