This is the view commonly understood and immediately sensible. It's the view I was taught and grew up with, and it's the view to which I still adhere when writi

This is the view commonly understood and immediately sensible. It's the view I was taught and grew up with, and it's the view to which I still adhere when writing (fwiw, I'm an adamant user of "himself" or "herself" for the singular). In this view, "them" is acceptable on an informal, common-usage basis. That said, linguists in recent years have been working out formal methods of acceptance for "themselves" as a singular-referring pronoun when the gender of the subject is unknown. See my previous comments about "them" as a free variable; this is the formalist's argument for the acceptability of "them." It is an argument advanced by some of the more influential logicians of the mid to late 20th century, such as W.V.O. Quine. It's an argument based more in symbolic logic than in traditional linguistics, but it's gained a fair amount of currency in the high-nerddom of syntax. It's by no means an established or generally accepted stance, however. The general, traditionally formal rule is that "them" is always plural, and the construction "singular subject = them" is a bit like saying "1 = >1," i.e., illogical.