Some people feel that English is a sexist language because it has no gender-neutral pronoun. For example: "Each student should bring his book to class." Some argue that the use of "his" is sexist. So some believe that you should say "Each student should bring his or her book to class." I personally think that's ridiculous, but I was wondering if there are any such issues in Russian.

Например:

Правильно сказать "Кто-то сделал что-то" или "Кто-то сделали что-то"?

и т.д.