Over the years, more and more people have given up the fight in support of pronoun agreement in the context of the third person plural/singular. For some, it’s a matter of avoiding gender-specific language, as in the following:
“The student who stays out too late Thursday night risks missing their early Friday classes.”
My advice has always been to pluralize the antecedent to make the third person plural possessive agree.
“Students who stay out too late Thursday night risk missing their early Friday classes.”
But what if the antecedent is an indefinite pronoun?
“Nobody wants to miss their classes.”?
Well, Geoffrey Pullum discusses just that topic in the Chronicle of Higher Education‘s Lingua Franca blog. I think I’ll agree with Pullum, not only because it means fewer marks on students’ drafts but also because Pullum makes sense.