If you do not know what their sex is, they makes sense.
The pronoun “they” is plural, so, no, it does not make sense. Use the default masculine or say “he or she.”
The left uses “they” along with their stupid preferred pronouns nonsense.
The convention in proper English for generations is when the sex of the person is unknown, one uses the male pronoun. This is not sexist or discriminatory, it is simply a convention for communicating that only a single individual is being referred to. If one knows the person is female, then use the female pronouns.
Under no circumstances does it make sense to call a single individual “they.”
“If you do not know what their sex is, they makes sense.”
Or, if the media wants to hide/withhold it.