“Never accept a drink from a urologist” (a urologist is a physician who specializes in diseases of the urinary tract) is a jocular saying that has been printed on many images. American humorist Erma Bombeck (1927-1996) and others were featured in a June 21, 1981 article in the San Francisco (CA) Sunday Examiner & Chronicle and other newspapers on “The best advice their fathers ever gave,” and Bombeck answered:
     
“The best advice my father ever gave me was to learn how to laugh, learn how to accept people as they are and not how you want them to be. And, lastly, never accept a drink from a urologist.”
     
“‘The Law of Common Sense’ Never accept a drink from a urologist” was posted on the newsgroup bit.listserv.banyan-l on June 25, 1998.
   
   
Wikipedia: Erma Bombeck
Erma Louise Bombeck (née Fiste; February 21, 1927 – April 22, 1996) was an American humorist who achieved great popularity for her newspaper column that described suburban home life from the mid-1960s until the late 1990s. Bombeck also published 15 books, most of which became bestsellers. From 1965 to 1996, Erma Bombeck wrote over 4,000 newspaper columns, using broad and sometimes eloquent humor, chronicling the ordinary life of a midwestern suburban housewife. By the 1970s, her columns were read twice-weekly by 30 million readers of the 900 newspapers in the U.S. and Canada.
 
21 June 1981, San Francisco (CA) Sunday Examiner & Chronicle, “The best advice their fathers ever gave” by Anthony Bowen, Scene sec., pg. 4, col. 1:
ERMA BOMBECK: The best advice my father ever gave me was to learn how to laugh, learn how to accept people as they are and not how you want them to be. And, lastly, never accept a drink from a urologist.
     
Google Books
599 Things You Should Never Do
By Ed Morrow
Chicago, IL: Contemporary Books
1995
Pg. 66:
“Never accept a drink from a urologist.”
Erma Bombeck (1927- ), quoting her father, as quoted by Anthony Brown in an article for the Los Angeles Times syndicate
     
Google Groups: bit.listserv.banyan-l
ST log
Myers, Robert
6/25/98
(...)
“The Law of Common Sense”
Never accept a drink from a urologist.
 
Google Books
Just Like Dad Says:
A Book of Dad’s Wit
By Geoff Tibballs
London, UK: Ebury Press
2009
Pg. ?:
My father used to say, ‘Never accept a drink from a urologist.’
Erma Bombeck
 
Google Books
Food and Drink:
A Book of Quotations
Edited by Susan L. Rattiner
Mineola, NY: Dover Publications
2012
Pg. 6:
Never accept a drink from a urologist.
ERMA BOMBECK
     
Twitter 
Janie Lopez
@janielo
Funny Laws
The Law of Common Sense:
Never accept a drink from a urologist.
The Law of Self Sacrifice:
When you starve with a tiger, the tiger starves last.
The Law of Volunteering:
If you dance with a… https://www.facebook.com/1293104628/posts/10219282364791898/ …
3:02 PM - 15 Apr 2019