Where does (or do) the apostrophe and "s" go for the plural possessive of mother-in-law?

Question

An example context (ignore my own punctuation):

"Mothers-in-laws' meddling in their childrens' marriages is often overstated...."

Answer 1

Mother's-in-law (if there is only one) - mothers'-in-law if plural possessive

Answer 2

mothers-in-law is the plural

mother-in-law's is the singular possessive

If you are describing a group of mothers-in-law, I believe the plural possessive would then be:
mothers-in-law's

It would be easier if you could describe a context for when this might be used, as I can't think of one offhand. :)

EDIT: Is this a regional/country variation? As an English major (several years back), I have never used "mother's-in-law", or been corrected for using "mother-in-law's" ? Just wondering, from the midwest USA

Answer 3

Plural Possessive is always : s'. But how can you have more than one mother-in law?

Answer 4

Tracymoo... is correct. Plural possessive is mothers'-in-law.

Answer 5

There is no apostrophe in the plural. It is spelled "mothers-in-law". For the possessive case, it would be "mother-in-law's"

-MM

Answer 6

If it is singular then mother's-in-law
My mother's-in-law house is across town.

If it is plural then mothers'-in-law
At least one of all mother's-in-law daughters are married.

Answer 7

Mothers'-in-law. (And "Mother's-in-law" if singular.)

"Mother" is the noun and is pluralized, "in-law" is the adjectival construction, and is not pluralized.

Answer 8

mother's-in-law and in plural : mothers'-in-law

Answer 9

mother's-in-law