Unnamed Mom (mother)
Bertram is the son of two women, who used Peter Griffin's seminal donation, to produce him. He has become the sworn enemy of Stewie Griffin. He first debuted in "Emission Impossible", where he existed only as a sperm cell, but wasn't officially born as a human baby until "Sibling Rivalry". He was ultimately destroyed in "The Big Bang Theory", when Stewie erased him from existence.