It is not easy to distinguish the twins from each other. This table should do the trick:
According to Marge, Patty chose a life of celibacy, while Selma had celibacy thrust upon her.
Like her twin sister Patty, Selma is an avid (and sometimes maniacal) fan of the eighties TV series MacGyver.
Selma once took the Simpson children on a disastrous trip to the Duff Gardens theme park, where Bart manhandled several animatronic characters and Lisa went on a psychedelic trip after ingesting "water" from a boat ride. Selma cares for her deceased aunt's iguana Jub-Jub.
See also: List of characters from The Simpsons