Just fix plural mothers in word, goodness this is offensive.

Apparently just asking this question required two hours of unpaid labor on my part, as well as running a fricking experiment for your guys.  I just wanted to turn the rule off for this, but apparently you won't let me do this so please fix Word so it stops asking me for worse grammar. Because tech support sent me here, I already ran the experiments for you. Apparently you can have plural fathers, and parents, but not mothers, which is fricking great. Value judgements from word.  

The solutions make the grammar WORSE, and some people have more than one mother. It's not even cultural. Some people have a stepmother and a birth mother

Persists in android as well:

It's just fricking lame, and all I wanted was to be able to turn the rule causing this off as it was annoying for the project I was working on. Techsupport told me to come here, and if I am now your QA person I would like to be paid, thanks.