Humour and jokes about one's mother-in-law (the mother of one's spouse) are a mainstay of comedy. The humour is based on the premise that the average mother-in-law often considers her son-in-law to be unsuitable for her daughter (or daughter-in-law unsuitable for her son), and usually includes the stereotype that mothers-in-law are generally rude, overbearing, obnoxious, and/or unattractive.[1]
British comedians such as Les Dawson and Jim Davidson have often used them, and many television sitcoms have featured stereotypical mothers-in-law.
There is evidence that this joke dates back to Roman times: Satire VI by Juvenal says that one cannot be happy while one's mother-in-law is still alive.[1] Most of the mother-in-law jokes are easily translatable to other languages and are easily understandable in most European cultures.
In a book on cartooning written by Dave Breger, the author lists a series of "tired gags", and gives a suggestion on how to exploit them. In his illustration, Breger and his wife go to a museum and see a Tyrannosaurus skeleton. Mrs. Breger says, "And no funny remarks, please, about that Mother called or something..."[2]
A study of mothers-in-law by Pamela Cotterill found that "they tended not to be upset by jokes because they seemed so far fetched they couldn't apply to them, but they didn't find them funny". Cotterill also found that daughters-in-law did not find them funny either, largely because they saw that one day the jokes could be applied to them.[1][3]
The jokes are considered offensive by some. A widely reported case is that of the London borough where, in 2010, a workshop leaflet called "Cultural Awareness: General Problems" advised against using them. The leaflet states that "mother-in-law jokes, as well as offensively sexist in their own right, can also be seen as offensive on the grounds that they disrespect elders or parents."[4][5]