@me_iz_unicorn Вот что Google style guide рекомендует, например:
Don't use gender-specific pronouns...
In particular, don't use "he," "him," "his," "she," or "her" as gender-neutral pronouns, and don't use "he/she" or "(s)he" or other such punctuational approaches. Instead, use the singular "they."
Singular "they" has been in use for a long time; for example, Jane Austen used it, and in 2015 the Washington Post adopted it as part of their official style.