According to some language analysts (B.Ilyish, F.Palmer, and E.Morokhovskaya), nouns have no category of gender in Modern English. The difference between such nouns as actor and actress is a purely lexical one.
Still, other scholars (M.Blokh, John Lyons) admit the existence of the category of gender. Prof. Blokh states that the existence of the category of gender in Modern English can be proved by the correlation of nouns with personal pronouns of the third person (he, she, it). Accordingly, there are three genders in English: the neuter (non-person) gender, the masculine gender, the feminine gender.