Georgie: Admit it, he's adopted.
Sheldon: How can I be adopted when I have a twin sister? Think, monkey, think.
Missy: I wish I was adopted.
Mary: That can still be arranged.
When Sheldon is putting his mittens on at the table he his seen putting the first one on and the second one is on the table, the shot changes and the mitten is no longer on the table. He raises his hands and both hands have mittens on them.
Zoe Perry, who plays Sheldon's mother Mary, is the daughter of Laurie Metcalf, who plays Mary on The Big Bang Theory.