Both Mark Frauenfelder of BoingBoing and Alex Boese of the Museum of Hoaxes, following threads from the Heresy Corner blog (see links below), commented today on the probability that the twins separated at birth who found each other later in life, fell in love and got married, much to the horror of seemingly everyone, since, as the story goes, their marriage was immediately annuled, is undoubtedly an urban legend.
Links from Heresy Corner:
image: Twins Insurance