>I don't get it....
The person telling the joke is assuming the blonde's mother, and her sister's mother, are the same person. Whether that assumption is funny, is a matter of taste :)
Regards. Al
"Violence is the last refuge of the incompetent." -- Isaac Asimov
"Never let your sense of morals prevent you from doing what is right." -- Isaac Asimov
Neither a despot, nor a doormat, be
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