"Sibling Rivalry '' is the 22nd episode of the fourth season of the animated comedy series Family Guy. It originally aired on Fox in the United States on March 26, 2006. The episode follows Stewie as he battles with his half - brother, Bertram (voiced by Wallace Shawn), who is born to two lesbians after Peter donates sperm. Meanwhile, Lois begins excessive eating after Peter undergoes a vasectomy and loses his interest in sex.
family guy episode where peter gets a vasectomy
Sibling Rivalry