@jwfacts:
Just another thought: The scripture in Job, even though it may not be a birthday celebration, may help with another attack I've seen thrown from the JW camp - mainly that a birthday is a celebration of the individual, a raising up of that individual to a level that shouldn't be done. Praise is for Jehovah... etc.
If each of Job's children had "his day" then that line of reasoning doesn't work.
MeanMrMustard