On the surface, your daughter's reaction does seem a little extreme, but if you have been this interfering over the baby's name, which, as others have said, is the choice of the parents and not the grandparents, have you been equally interfering in other areas of her life? Your comment about her being rather superficial make you sound as if you don't really see her as an adult in her own right even at forty. Your whole post comes across as Mother Knows Best. If l am wrong then I apologise and, of course, l am sorry that it has come to this, but there are times when we all need to acknowledge when we are at fault and to me this fallout over the baby's name sounds like the straw which has broken the camel's back.