It recent decades, it has become more common to see the word “they” in place of “he” or “she”, in sentences like this:
When a user logs on, they enter a username and password.
That’s less awkward than alternatives like “he or she enters a password”, “he/she enters a password”, “he enters a password” etc.
However, “they” still sounds a little weird to many ears, as we predominantly think of it as a plural pronoun. Others are more militant in their opposition to “they” in such contexts, declaring it just plain wrong.
So is it wrong? Is it just another bastardization of English, pandering to overzealous political correctness? Actually, probably not.
It’s surprising to find that this use of “they” goes back a long way—perhaps further than you might have guessed. It was, indeed, used in the King James Bible, written way back in the early 1600s:
… if ye from your hearts forgive not every one his brother their trespasses. –Matthew 18:35
So historically, this usage of they/their is fine. Apparently, it was a group of grammarians in the 1700s who decided that this usage of a plural word was inappropriate with a singular noun. (The recommendation was to use “he” and just live with the gender bias.)
Avoiding both plural pronouns but also gender bias can lead to absurd sentences (as noted on the Merriam Webster site), such as—
Everyone should do his or her best in whatever situations he or she finds himself or herself in.
It’s worth asking ourselves, then, why there’s resistance to the use of “they” with singular subjects. “Because they is plural”, someone might protest. But words mean whatever we decide they mean, and plenty of words have various meanings in different contexts. Words get their meaning from how they are used, and if “they” has been used for centuries to refer to singular entities, then it simply does refer to singular things!
Anyhow, that’s my take on it. I’m now trying to train myself to use “they” in this context more often and not shy away from it. And if anyone doesn’t like that, then they can just “suffer in their jocks”, as we say in Australia.