Palmer and Miannetta were listed on the 1940 census in Bloomer, Bloomer City, Chippewa, Wisconsin. It appears they died in Chelsea, Taylor, Wisconsin. You would need to send for their death certs. to see if it list their parents, unless you know who they are. You also might try to find obits for them.
name: Palmer Olsen
event: Census
event year: 1940
event place: Bloomer, Bloomer City, Chippewa, Wisconsin, United States
gender: Male
age: 26
marital status: Married
race (standardized): White
relationship to head of household (standardized): Head
birthplace: Wisconsin
estimated birth year: 1914
residence in 1935: Same Place
head Palmer Olsen Male age 26 Wisconsin
wife Minetta Olsen Female age 23 Wisconsin
son Delmar Olsen Male age 1 Wisconsin
daughter Patricia Olsen Female age 0 Wisconsin
name: Minetta Olsen
event: Census
event year: 1940
event place: Bloomer, Bloomer City, Chippewa, Wisconsin, United States
gender: Female
age: 23
marital status: Married
race (standardized): Negro
relationship to head of household (standardized): Wife
birthplace: Wisconsin
estimated birth year: 1917
name: Delmar Olsen
event: Census
event year: 1940
event place: Bloomer, Bloomer City, Chippewa, Wisconsin, United States
gender: Male age: 1
marital status: Single
race (standardized): White
relationship to head of household (standardized): Son
birthplace: Wisconsin
estimated birth year: 1939
residence in 1935:
head Palmer Olsen Male age 26 Wisconsin
wife Minetta Olsen Female age 23 Wisconsin
son Delmar Olsen Male age 1 Wisconsin
daughter Patricia Olsen Female age 0 Wisconsin
name: Patricia Olsen
event: Census
event year: 1940
event place: Bloomer, Bloomer City, Chippewa, Wisconsin, United States
gender: Female
age: 0
marital status: Single
race (standardized): White
relationship to head of household (standardized): Daughter
birthplace: Wisconsin
estimated birth year: 1940
first name: Palmer
last name: Olson
birth date: 28 September 1913
social security number: 395-09-3506
place of issuance: Wisconsin
last residence: Chelsea, Taylor, Wisconsin
zip code of last residence: 54419
death date: January 1984
estimated age at death: 71
first name: Miannetta
middle name: M
last name: Olson
birth date: 22 November 1916
social security number: 392-20-3763
place of issuance: Wisconsin
last residence: Chelsea, Taylor, Wisconsin
zip code of last residence: 54419
death date: 18 February 2007
estimated age at death: 91