DEAN: Well, what if it’s for a really special occasion?
RORY: Well, that special occasion better include my being relocated to a plastic bubble if my grandmother’s gonna let me out of dinner.
Rory is referring to the disease severe combined immunodeficiency, a rare genetic disorder where the sufferer remains extremely vulnerable to infectious disease due to having an immune system so compromised it is effectively absent. It is sometimes called “bubble boy disease”, because high-profile patients became known for living in sterile environments.
The disease became well known after the 1976 television film The Boy in the Plastic Bubble, directed by Randal Kleiser, and with John Travolta in the title role. The film was inspired by the real-life cases of David Vetter (1971-1984) and Ted DeVita (1962-1980); DeVita actually had severe aplastic anemia, which is able to be better treated now.
Although the movie wasn’t shown on television during Rory’s childhood, bootleg copies were widely available on video, and Lorelai may have obtained one.