One response to this question indicated that you should not rely on anything other than the birth date and name of the person on the birth certificate because one does not know who supplied the information. Surely, that is far too general a statement? No doubt it will depend on the jurisdiction from which the birth certificate comes, but with certificates from England and Wales it is always clear who supplied the information, and it is rare indeed that the informant is not either the mother or the father of the child. Since it is information given within a very short time of the birth by somebody having first-hand knowledge how can it be anything other than primary data? I certainly understand the argument as it relates to a death such as a date of birth being supplied by an informant when registering a death, and I think this whole argument is a major reason why I have never seriously looked at becoming a professional genealogist. I realize this is not directly relevant to the list, and I am only mentioning it now because the statement was made on the list. Tim