Lavinia Warren (1841 – November 25, 1919) was an American proportionate dwarf and the wife of General Tom Thumb.
Warren was born at Middleborough, Massachusetts as Mercy Lavinia Warren Bump, a descendant of a French Catholic family named Bonpasse, of Governor Thomas Mayhew, and five Mayflower passengers: John Billington, Francis Cooke, Edward Doty, Stephen Hopkins, and Richard Warren — New England families which intermarried many-times over.
Lavinia and her younger sister Huldah Pierce Warren Bump had a form of proportionate dwarfism (considered to be desirable by sideshows and "museums" of that era owing to its perfectly miniaturized characteristics, with the same proportions as common larger people) caused by a pituitary disorder which seemingly occurs when close relatives (cousins) descended of identically replicating DNA (twins) produce offspring.
Lavinia's parents were 4th cousins, the mother being a 2nd great grandchild of married cousins, descended of a twin. The maternal 2nd great grandfather of Lavinia's father James Sullivan Bump, Medad Tupper born 1677, was a son of Thomas Tupper and Martha Mayhew.