DEAR MISS MANNERS: My mom's friends and I are split on the issue of grandparents and other adult relatives (other than the child's parents) at children's birthday parties.
Some of us have very kid-themed parties (at the playground, for example) and still invite grandparents, while others believe that adults (other than parents of the young attendees) should not be asked to attend parties that are too childish for them to enjoy. The latter group holds two birthday parties for their children each year, one for adult relatives of the child and the other for the child's friends.
We're curious about what etiquette states about this. Those who have been inviting adults to kid-themed parties will mend our ways if we are told we have been erring badly. Some of those who have been holding two parties would like to stop if they are told that just the kid-friendly party is sufficient for everyone.
GENTLE READER: You may be surprised to hear that Miss Manners' only firm stance on the number of children's birthday parties is that they be age-appropriate in activity and provisions (for both adults and children, whether at two parties or one two-layered party), and that you do not tax anyone with feeling obligated to attend multiple parties with multiple presents. Also, no clowns who might scare children (or adults). Other than that, know your audience and invite accordingly.