Question

Is it
Both of their mothers
Or
Both of their mother’ s

Answer 1

The correct answer would be “Both of their mothers.”

Step-by-step explanation:

To pluralize “mother”, you would simply need to add the “s” at the end of the word.
If the term “Mother’s” had an apostrophe in it, then the word would be possessive and it would refer to something in the mothers possession.

Hope this helps! :)