Here is the entry on it from The Times’s “Manual of Style and Usage,” a guidebook used by reporters and editors throughout the newsroom:
transgender (adj.) is an overall term for people whose current identity differs from their sex at birth, whether or not they have changed their biological characteristics. Cite a person’s transgender status only when it is pertinent and its pertinence is clear to the reader. Unless a former name is newsworthy or pertinent, use the name and pronouns (he, his, she, her, hers) preferred by the transgender person. If no preference is known, use the pronouns consistent with the way the subject lives publicly.
Susan Wessling, the deputy editor who supervises The Times’s copy editors, told me that there are two important considerations. “We want to respect the preferences of the subject,” she said, “and we want to provide clarity for readers.”
Toward that end, she said, “We’ll probably use more words than less.” In other words, The Times will explain the change in stories.
“We can’t just spring a new name and a new pronoun” on readers with no explanation, she said. She noted the importance in the stylebook entry of the words “unless a former name is newsworthy or pertinent,” which certainly applies here.