“Every student must submit his assignment by Friday.”
Generic 'he' vs. They/Their
Using 'he' to mean 'any person' excludes over half the population. 'They' is the accepted neutral alternative.
The comparisoni
“Every student must submit their assignment by Friday.”
More examplesii
A good manager listens to his team.
A good manager listens to their team.
Each user should update his password.
Each user should update their password.
The applicant must submit his documents.
The applicant must submit their documents.
Someone called — tell him I'll call back.
Someone called — tell them I'll call back.
Every employee is responsible for his own performance.
Every employee is responsible for their own performance.
The manager must submit their report. (When you know he's male)
The manager must submit his report. (Use the person's actual pronoun when known.)
The ruleiii
Use THEY/THEIR as a singular neutral pronoun when the person's gender is unknown, unspecified,…
Traditional grammar taught 'he' as the default for unknown gender. This rule has been widely rejected — 'they' as singular has been used by writers including Shakespeare, Jane Austen, and Chaucer.
Memory aidiv
You already use singular 'they' naturally: 'Someone left their bag here.' Notice you didn't say 'his bag'. That instinct is correct — follow it.