Common noun

Because a pronoun REFERS to a noun or TAKES THE PLACE OF that noun, you have to use the correct pronoun so that your reader clearly understands which noun your pronoun is referring to.

Therefore, pronouns should:

1.

Agree in number

If the pronoun takes the place of a singular noun, you have to use a singular pronoun.

INCORRECT: The girls brought her umbrella.

CORRECT: The girls brought their umbrella.

NOTE: Some find the construction "his or her" wordy, so if it is possible to use a plural noun as your antecedent and thus use "they" as your pronoun, it may be wise to do so.

If you do use a singular noun and the context makes the gender clear, then it is permissible to use just "his" or "her" rather than "his or her."

NOTE ALSO: Recently, the use of "they" and "their" as singular pronouns has become more popular.

This is due in part to the awkwardness of workarounds like "his or her" and in part to a broader cultural recognition that not all individuals identify themselves with the words "he" or "she." In fact, several official citation resources (i

what is a correct pronoun antecedent agreement

what is proper pronoun antecedent agreement