The gender of an object, thing or phenomenon is expressed with lexical, but not grammatical, means (boy – girl, man – woman, bull – caw; he-goat – she-goat; star – it; window – it, ship – it/she, etc.). Grammatically there is almost no sign to indicate the gender of a noun (the suffix -ess can be considered as an exception: steward – stewardess, actor – actress, etc.).
Some scientists, however, (for example, an American linguist Strand, a Russian linguist Bloch) consider Gender as a category of the English Noun as all the nouns can be substituted by the appropriate pronouns. Though it would not be really correct for the propriety of the Pronoun (to substitute the noun in accordance to the lexical gender the latter expresses) is shifted to the Noun. It can breed a certain confusion in the understanding of the problem of English Grammar.