“Presumed to be authentic by you maybe, but the fact is...”
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LOL, what you and I presume is immaterial.
I was speaking of federal law in general and the Federal Rules of Evidence in particular. They tell us that documents like birth certificates are legally presumed to be authentic unless proven to be forged in a court of competent authority.
And “proven to be forged” doesn’t mean proven to your satisfaction or to mine. It has a legal definition.
Under the law, the BCs are presumed to be authentic and under the law they have not been proven to be forgeries.
I expect that their status in your mind is different, but their legal status is indisputable.