[READINABLUESTATE]

That’s the whole point. The gender is unknown.
My father was an English professor.

Let’s ask the Otter.

[Petrosius]

That’s the whole point. The gender is unknown.

Then just refer to "the child." "They" is plural. While it might be suitable if the number is hypothetical, in this case it is clearly singular. "The child" is suitable and there is no sound reason to use the plural "they." This especially true today when "they" is being pushed as a non-binary pronoun. This political usage cannot be ignored.