"The employee believed their safety could not be guaranteed."
The sentence above has an apparently overt grammar error. The subject of the sentence, employee, is singular but the pronoun their is plural. Most business writers would catch this obvious error. Subjects and pronouns need to agree in number, so the sentence should be "The employee believed his or her safety could not be guaranteed."
The challenge with the corrected sentence is that it is awkward and it boxes individuals who do not identify as uniquely male or female into a category that doesn't fit for them. It's exclusionary, and style guides are addressing this.
Using they as a singular pronoun has become acceptable in some cases, especially as a gender-neutral pronoun.
The 2017 edition of The AP Stylebook — the style guide used most widely in business — stated:
“They/them/their is acceptable in limited cases as a singular and/or gender-neutral pronoun, when alternative wording is overly awkward or clumsy.”
For example, to avoid the specificity of an individual’s gender, this use of their is acceptable: “The employee believed their position was in jeopardy.”
The Washington Post addressed this in 2015:
“Allowing they for a gender-nonconforming person is a no-brainer. And once we’ve done that, why not allow it for the most awkward of those he or she situations that have troubled us for so many years?”
The Chicago Manual of Style now states:
“While this usage [they, them, their, and themselves] is accepted in those spheres [speech and informal writing], it is only lately showing signs of gaining acceptance in formal writing, where Chicago recommends avoiding its use. When referring specifically to a person who does not identify with a gender-specific pronoun, however, they and its forms are often preferred.”
Garner’s Modern American Usage recommends its cautious use:
“Where it can’t be avoided, resort to it cautiously because some people may doubt your literacy.”
Microsoft Manual and Style advises:
“Although . . . they for a singular antecedent is gaining acceptance. . . . Whenever possible, write around the problem.”
Grammarly polled their readers and most objected to the singular use of they. Admittedly, it can become awkward: "They is a talented artist."
As a comment below correctly noted, use the plural verb conjugation when using "they" to refer to an individual: "They are a talented artist." Or, just rewrite the sentence to avoid both a gender identification and the need for a pronoun: "The artist is talented." More on gender-neutral pronouns here.
One of the aspects of business writing that I love most is that it evolves to reflect appropriate information flow and awareness. Style Guides and writing blogs are clearly addressing this with a cautious endorsement of the singular they.
My recommendation now is to generally stick to standard grammar constructs and match singular pronouns with singular subjects and plural pronouns with pronoun subjects. But, do use they as a singular pronoun when it is respectful or more clear to do so.
Words matter. Including everyone respectfully in the discourse warrants bending this grammar rule.
Image Source: Grammarly