I've just met a comment with a link to a problem statement. There was such text in the statement:

Soon the professor realized that reconstructing Anatoly’s code and the test tree from his output was not a simple task and that the result might be ambiguous. You will have to help her find all possible reconstructions of Anatoly’s code.

Don't you see something weird here? I think it should be:

Soon the professor realized that reconstructing Anatoly’s code and the test tree from his output was not a simple task and that the result might be ambiguous. You will have to help him find all possible reconstructions of Anatoly’s code.

or:

Soon the professor realized that reconstructing Anatoly’s code and the test tree from his output was not a simple task and that the result might be ambiguous. You will have to help them find all possible reconstructions of Anatoly’s code.

I know that people either use the gender that is more common for a person, e.g. he for drivers and she for nurses, or just use they (my English teacher said they is correct). I've wandered across Wikipedia (here is one of the links: https://en.wikipedia.org/wiki/English_personal_pronouns#Use_of_he.2C_she_and_it), but haven't found anything about preferrable usage of female pronouns.

However, I've read really a lot of English statements, and everywhere the female pronouns are used! For children and professors, for drivers and miners, for rabbits and foxes, for everything and everyone. Why?