Lynn Liben, a psychologist at Penn State, has studied the effects of gender-coded language — English weaves it in by way of pronouns (she, his) but also identifying nouns (girl, uncle) and honorifics (Mr. and Mrs.) — for about 15 years. In a pair of studies conducted in preschool classrooms in 2008 and 2010, Liben found that when teachers emphasize a gender divide in speech — like saying, “Good morning, boys and girls” — children adopt more intense stereotypes about what boys and girls are supposed to do, and become less likely to play with children of a different gender at recess. “When they see adults talk about gender as a category system,” Liben says, “kids become more vigilant about making the distinction themselves.” Jill Soloway, creator of the Amazon series “Transparent,” is a fan of “they” as a corrective to that phenomenon. “A really interesting thought exercise is to say ‘they’ and ‘them’ for all genders,” she told The New Yorker recently. “The promise of this revolution is not having to say, ‘Men do this, women do this.’ ”

These gender-neutral constructions, which not so long ago may have sounded odd or even unthinkable to traditionalists, are becoming accepted as standard English. The Washington Post is one of the first to have taken up the cause, welcoming the singular “they” into the paper’s stylebook late last year. And in January, the American Dialect Society voted the singular “they” its 2015 Word of the Year, noting its “emerging use as a pronoun to refer to a known person, often as a conscious choice by a person rejecting the traditional gender binary of he and she.”

But central to the appeal of the singular “they” is that it’s often deployed unconsciously. It’s regularly repurposed as a linguistic crutch when an individual’s gender is unknown or irrelevant. You might use it to refer to a hypothetical person who, say, goes to the store and forgets “their” wallet. That casual usage has a long history — it has appeared in Chaucer, Shakespeare, Austen and Shaw. It wasn’t until 1745, when the schoolmistress-turned-grammar-expert Ann Fisher proposed “he” as a universal pronoun for a person of unknown gender, that the use of “they” in the same circumstance was respun as grammatically incorrect. “The Masculine Person answers to the general Name, which comprehends both Male and Female; as, any Person who knows what he says,” she wrote.

It’s precisely the vagueness of “they” that makes it a not-so-ideal pronoun replacement. It can obscure a clear gender identification with a blurred one. Think of genderqueer people who are confident in their knowledge of their own gender identity as one that simply doesn’t fit the boxes of “he” or “she”: Calling all of them “they” can make it sound as if someone’s gender is unknowable; it’s the grammatical equivalent of a shrug. In December, the Post copy editor Bill Walsh called “they” “the only sensible solution to English’s lack of a gender-neutral third-person singular personal pronoun,” with “sensible” being the key word. The singular “they” gained favor with The Post’s standard-bearer partly because the presumptive “he” “hasn’t been palatable for decades,” but also because a generic “she” feels “patronizing” and “attempts at made-up pronouns” — like “xe,” “xim,” and “xir” — strike Walsh as “silly.” The New York Times hasn’t officially adopted “they,” but The Times’s standards editor, Phillip B. Corbett, thinks it’s likely to earn a place in the paper’s stylebook as usage evolves. “Eventually, I assume, certain forms will become widely adopted, and that’s the point when it would make sense for us to set out formal style rules,” he told me. “My guess — just a guess — is that ‘they’ is far more likely to become the default pronoun in these cases, rather than ‘xe’ or other neologisms.”