The correct plural is fathers-in-law .
Fathers is the noun, in law the adjective; fathers in law, not father in laws which implies one father, but with multiple relationships.
The possessive form of daughter-in-law is daughter-in-law's.Example: My daughter-in-law's name is Margaret.
The possessive form of the singular noun 'daughter' is daughter's.example: This is a gift for my daughter's birthday.
The possessive form for the noun brother is brother's.Example: My brother's daughter is my niece.
In English there are no masculine or feminine forms. English uses gender specific nouns for male or female.The gender specific noun for the husband of your daughter is son-in-law.The gender specific noun for the wife of your son is daughter-in-law.
The singular possessive form is heart's; the plural possessive form is hearts'.
The possessive form of daughter-in-law is daughter-in-law's.Example: My daughter-in-law's name is Margaret.
The plural form of the noun daughter-in-law is daughters-in-law.The plural possessive form is daughters-in-law's.Example: Both of my daughters-in-laws degrees are in education.
The possessive form for the compound noun daughter-in-law is daughter-in-law's.Example: My daughter-in-law's shop will do my hair for free.
The possessive form of the singular noun 'daughter' is daughter's.example: This is a gift for my daughter's birthday.
The plural possessive form is fathers-in-law's.
The correct plural possessive form for "daughter's" is "daughters'."
The possessive form of the plural noun sons-in-law is sons-in-law's.example: Both of my sons-in-law's birthdays are on the same day.
The possessive form for the plural noun brothers-in-law is brothers-in-law's.Example: I had the work done at my brothers-in-law's body shop.
by adding s to daughter
The possessive form of the singular noun 'daughter' is daughter's.example: This is a gift for my daughter's birthday.
The possessive form for her sister-in-law is her sister-in-law's.Example: She borrowed her sister-in-law's car.
The possessive form of the noun sister-in-law is sister-in-law's.Example: I borrowed my sister-in-law's car.