Q: Which of these sentences is correct? (1) “Select ‘yes’ if you plan on bringing guest(s) in addition to the one listed above.” (2) “Select ‘yes’ if you plan on bringing a guest(s) in addition to the one listed above.”
A: Neither #1 nor #2 works, we’re sorry to say.
There’s no graceful way to use the parenthetical plural—“(s)”—here without a rewrite. Perhaps, “Select ‘yes’ if you plan on bringing any additional guest(s).”
As volunteers on land-use commissions in our New England town, we’ve come across many parenthetical plurals in regulations.
We don’t particularly like them, but a parenthetical plural can be helpful when it doesn’t disrupt the rest of the sentence.
The “(s)” leads to trouble, for instance, if it’s tacked onto a noun that’s the subject of a verb or that has a singular article (“a” or “an”).
The Chicago Manual of Style once answered a question similar to yours on its online blog. Here’s the reply:
“A term ending in ‘(s)’ is both plural and singular. If you must use such a device (and it can be a useful shorthand), you have to be prepared to adjust the surrounding context as necessary: for example, ‘the award(s) is (are) accounted for.’ A parenthetical plural verb must correspond to the parenthetical ending.”
The conclusion: “In general, avoid such shorthand unless it can be used simply and effectively, as in the following example: “Place an ‘about the author(s)’ statement on the copyright page (usually page iv).”
One more comment. Parenthetical plurals are particularly awkward when used in a series, or added to nouns ending in “y.”
Here’s an extreme example: “The sculptor(s) has (have) to know the type(s) of marble used, the place(s) of origin, and the stress(es) it (they) can withstand.” In such a sentence, it’s simpler and more elegant to use the generic singular throughout.
As for using a parenthetical plural with an irregular plural—like “woman(en)” or “child(ren)”—forget it.