The plural form of "vagina", "vaginas" is missing from the en_US dictionary. "vaginae" is currently the only accepted plural form.
Note: present in the GB dictionary.
I consider vaginas a variant of vagina. I have a general policy of not adding variant forms to the dictionary. I make exceptions on occasion, especially for plurals of this form, but I need some proof that both forms are in common use or that dictionaries disagree which is the preferred form.
I am marking this as "Wont Fix", I will eventual close this bug unless I find such proof.
I don't know about the project's policies, but I'd be happier if my spell checker wouldn't complain about correctly spelled common words.
Oxford says "noun (plural vaginas or vaginae /-niː/)", and wiktionary says "vagina (plural vaginas or vaginae or vaginæ)" suggesting that "vaginas" is a more common form than vaginae.
Merriam-Webster reverses the order, suggesting that vaginae is more common
I'd also like to say that it does look a bit bad politically when you type "vaginas and penises" in a text area and the spell checker only complains about "vaginas". That's how I found this issue.
Also, a google search yields 12800 results for "vaginae" and 3340000 for "vaginas", making the latter roughly 260 times more popular.
And COCA (Corpus of Contemporary American English) agrees with you. Will fix by most likely letting both forms in.
Fixed in svn commit #180.