I was in the very awkward position today of trying to find out the sex of a coauthor of an article for which I was sending a revision letter. I wanted to include in the letter that the doctor needed to update their financial disclosure and wanted to give instructions on how to do so.
I couldn't use third-person plural pronouns or "his/her" because the company objects to those uses. In order to avoid really awkward phrasing, I wanted to find out this person's sex so I could use the correct pronouns, and the person's name was not giving me any clues.
I eventually found information about the person's sex and completed the instructions with the correct pronouns. This situation highlighted for me the English language's need for a broadly accepted gender-neutral pronoun. Third-person plural pronouns are fine to me, if only conservative institutions would stop having grammatical fits about them.
Interestingly enough, I mostly avoid the subject of people's sex in my job because pretty much everyone we deal with is a doctor, so we just address them by that title.