In some languages, words can be referred to as being masculine, feminine, or neuter. In English, pronouns (words that replace nouns to avoid unnecessary repetition) and possessive adjectives are the only parts of speech that express gender. He, she, hers, and his are some examples. 

In English, nouns do not have grammatical gender. However, when one replaces a noun that indicates gender with a pronoun, the pronoun refers to the sex of the noun. Here is an example sentence: When John got home he fed his dogs. John refers to a male person with the pronoun he being used to replace the name, while his is the possessive adjective indicating that John is the owner of the dog. Nouns that do not express gender are replaced by the gender neutral pronoun it. An example is: I caught a ball at the game today but lost it afterwards. You can see here that the neuter noun, ball, is replaced with the neuter pronoun it. 

Examples:

• The books belong to Maria, not Charles. The books are hers (Maria’s), not his (Charles’).
• She went to the library to pick up her son’s books.
• What is Elias waiting for? Does he want us to go in with him?