In article , (Adrian) wrote:

"They" is used as a (slightly awkward) gender-neutral singular,
rather than "he/she/it", or "s/he" or some similar godawful murdering
of the language.

http://www.crossmyt.com/hc/linghebr/austheir.html#X1a

Interesting. However, hallowed by age though it may be, I find its use
considerably uglier than "he or she" or the other alternatives you
mention. But it takes all sorts....

--
Peter Beale