DEAR MISS MANNERS: My mother is throwing us a baby shower on her birthday. How should I acknowledge this? Or do I?
GENTLE READER: By saying "Happy birthday."
Miss Manners hopes and trusts that your mother picked this date out of a desire to do something enjoyable on it -- and not for any other (passive-aggressive) motives. If that is the case (and really, even if it is not), give a toast to thank your hostess -- and add that it is also her birthday. That way, your guests can give their well wishes, but will not have to feel bad for not bringing another present.
Miss Manners' own gift to both you and your mother is not to point out that relatives should not actually be throwing showers as -- much like giving your own birthday party -- it looks like fishing for presents.