At what age is it appropriate to invite a child to a birthday party without a parent? -M

I believe that ages 4 and up can go to a party without a parent, anything younger then that may be a little difficult.  One of the biggest reasons is that generally 4 year olds are potty trained and generally are okay being without their parents.  My son actually just went to his first child only party and it was all 4 year olds.  If you are throwing the party, I would suggest keeping the party smaller (6 kids or less) if the children are under 5 and their parents will not be with them.