Old English had a system of grammatical gender similar to that of modern German, with three genders: masculine, feminine, neuter. Determiners and attributive adjectives showed gender inflection in agreement with the noun they modified. Also the nouns themselves followed different declension patterns depending on their gender. Moreover the third-person personal pronouns, as well as interrogative and relative pronouns, were chosen according to the grammatical gender of their antecedent.
When to Use He, She or It?
The personal pronouns he, she, it and the relative pronouns who, which are gender-sensitive:
John is late ~ He is late.
Mary is late ~ She is late.
John and Mary are late ~ They are late.
Here the choice of pronoun is determined by the sex of the person being referred to. However, this distinction is lost in the plural.
Gender differences are also manifested in possessive pronouns (his/hers) and in reflexive pronouns (himself/herself).
The natural distinctions reflected in such pairs as brother/sister, nephew/niece, and king/queen have no consequence for grammar.
While they refer to specific sexes, these words are not masculine or feminine in themselves.