As a matter of language use only, the phrase "They are coming over to my house later". Should I expect one person, or multiple people? Should I go out and grab a 6-pack of beer for my visitor(s) or a case? Easily clarified, and I'm happy to use people's preferred pronouns, but let's not pretend there isn't the loss of precision there.
A piece of text does not use they/he/she without first establishing the noun that these will reference. The problem you are referring to does not happen if you write correctly.
Pronouns refer back to some previous noun phrase. Saying “she is coming over to my house later” would also be a weird and confusing thing to say without first establishing who you are talking about.
In technical writing you might say something like “The user will enter their password…”, where the pronoun “their” of course refers back to “the user”.
