My previous perspective had been that I was there to teach them to abide by the MLA style, and that the MLA style did not (yet) allow for the singular use of "they." Therefore, I have been marking this as a pronoun/noun error on papers for years. As far as I can determine, the MLA, Chicago, and APA style manuals all still recommend "he or she" or "he/she" or making the subject plural. The Chicago Style Manual states:
A singular antecedent requires a singular referent pronoun. Because he is no longer accepted as a generic pronoun referring to a person of either sex, it has become common in speech and in informal writing to substitute the third-person plural pronouns they, them, their, and themselves, and the nonstandard singular themself. While this usage is accepted in casual contexts, it is still considered ungrammatical in formal writing.The Chicago Style Manual recommends all the usual work-arounds: "he or she," plural subjects, imperative mood, rewrite the noun, revise the sentence, etc. I couldn't find as clear a statement out of the MLA or APA, but my understanding is that they offer the same options. The textbook I'm using for my class, The Little Seagull Handbook, offers these same work-arounds.
My job, as I saw it, was to teach them to learn to use the MLA style and their handbook, and so I followed its rules.
However, there is one big problem with the he/she-type work-around: it leaves out people who do not use male or female pronouns to describe themselves. And in the transgender community, use of alternative pronouns is becoming more common, particularly use of "zhe" or "hir." Not everyone considers themselves as someone either male or female--we don't all fit neatly into two little boxes. I could have students list all the pronouns, but as awkward as "he or she" is, certainly something like "he, she, zhe, or hir" would be more awkward.
There's an interesting story here about how we took a situation that was understood as sexist--the use of "he" to mean people of all genders--and then created a popular usage, "he or she," that was still discriminatory. And the grammar handbooks are still fighting the first problem and sometimes not even acknowledging the second one. For example, the Little Seagull Handbook says, "Sexist language is language that stereotypes or ignores women or men... Writers once used he, him, and other pronouns as a default to refer to people whose sex was unknown to them... Use both masculine and feminine pronouns joined by or." The Chicago Manual of Style similarly gives this as an option without recognition of the justice problem that it creates in section 5.225--Nine techniques for achieving gender neutrality: "Use he or she (sparingly)."
There's one clear answer to this justice problem, and it's the one they all avoid: "they." I try to avoid it in formal writing, but I do it in speech all the time. It's being used commonly in speech, and grammar rules should follow usage, not dictate usage, is one argument. It's a similar situation, one can argue, to what happened with the word "you." "You" was originally a plural pronoun, and the singular was "thou." Now we use a plural pronoun as a singular one with no issue, except for the need to create a new plural such as y'all. (Heavens, let's hope we don't get a "th'all" emerging!)
We don't really, however, use "they" in a complete singular way. We switch our sentences mid-stream to plural. So we don't take the sentence, "A student can use whichever pronoun he or she wants" and replace "he or she" with "they" and say, "A student can use whichever pronoun they wants." We say, rather, "A student can use whichever pronoun they want." We change the verb there at the end to reflect the fact that "they" is a plural pronoun. If I'm allowing for a singular "they" it should be followed by a singular verb, yes? But that's not what we're doing in speech. And we're not going to drop "he" or "she" as pronouns anytime soon and just move to totally using they and having plural verbs for singular subjects. So it's still all mixed up.
I've explained all this to my students, and told them that I want them to learn to use the style recommended and that I think this will change in the next few years and the style manuals will accept "they" as a gender-neutral singular pronoun, but until they do, I want them to be aware of how they're using their pronouns and follow the style manual.
But I'm swayed now by the justice argument. I was told of a situation in which the University of Michigan, my alma mater, dealt with this in a policy and ended up rewriting the sentences to avoid "he or she" or the singular "they" in order to be both grammatically and politically correct, when the justice advocates and the rhetoricians couldn't agree. The UU Ministers Association, I learned recently, embraces the singular "they" as a solution.
I would like to allow my students to use the singular "they," but at the same time I want them to be aware of what they're doing. I'm thinking of some sort of solution where they indicate their awareness through asterisks or brackets or italics: they, *they*, [they]. That would show they're aware of the singular pronoun, and I would like them to be. But that's as disruptive to the eye, on an aesthetic level, as people would think something like "z/s/he" would be.
So what will I do? I think, in the end, there's only one solution: explain it all, but let the student do whatever they want. There's still no reason I can't crack down on apostrophes. Thank goodness, because as fond as I was of pointing out pronoun/noun disagreements, the apostrophes are where my real passion is.