I’ve come across a number of articles lately — here and here and here, for instance — arguing that it’s perfectly correct to use “they” as a generic singular pronoun. I find these arguments compelling, and indeed have long noticed that the British exercise more freedom in this matter than Americans do. But . . . I can't do it myself. Just can't. I’ve spent too many years thinking it wrong and doing the “he or she” thing to change now.
On the other hand, it’s nice to think that I have one less common error to correct when I’m reading my students’ papers.