Recorded in over forty spelling forms from Lambert, Lambard and Limprecht, to Lambrich, Lambertini and Lemmens, this surname is almost certainly of very early German origins. As a surname it started life in the 12th century, but the derivation is from a pre 5th century personal name.
Sheldon was raised in Galveston, Texas along with his elder brother and fraternal twin sister (Missy) by his mother, Mary Cooper, an overtly devout Evangelical Christian; and George Cooper, an alcoholic who was never around.
Sheldonâs twin sister is Missy Cooper. And, she is the direct opposite of her brother. She appears only in the Season 1 episode, The Porkchop Indeterminacy. But after that she was mentioned in a couple of episodes but she is not seen anymore. In S07E11 (The Cooper Extraction), Missy gives birth to a boy in Texas.