While some languages categorize nouns based on their meaning or attributes, such as whether they refer to animals or humans, or their biological sex, other languages rely more heavily on morphological distinctions, where grammatical gender is determined by the structure of the word rather than its semantic meaning. For example:

Grammatical gender in English can be distinguished into four categories:

Masculine gender refers to a male figure or a male member of a species. For example: man/brother/dad/ox.

At times, certain nouns may not inherently possess a feminine or masculine gender, yet they are metaphorically assigned female or male pronouns. This is particularly true for tools, computers, or robots, which are often given masculine gender (although feminine gender is also possible).

Feminine gender refers to a female figure or female member of a species. For example: mother/sister/woman/cow.

Certain nouns may lack inherent feminine or masculine gender, yet they are metaphorically assigned female pronouns. This is commonly seen with vehicles (especially ships and boats), nations (such as "Mother Russia"), and the earth (referred to as "Mother Earth"), which are often considered feminine.

Neuter refers to words that are neither feminine nor masculine, like inanimate objects such as rock, table, and comb; animals, like dog, cat, and bear; humans (only a fetus whose gender is not known yet).

In modern times, people often prefer to use gender-neutral language that does not specify a particular gender. While certain jobs may historically have been associated with a specific gender, such as "postman" being seen as a male job, there are no jobs that are exclusively designated for one gender. Therefore, people often opt to use gender-neutral terms to refer to such notions. For example:

We should know that the gender of the noun affects the pronouns as well as the possessive determiners used with it.

Now, take a look at some examples:

Look at the following examples:

Traditionally, people used 'he/his' for unknown genders, but this is not very acceptable in modern times.

The above is correct, but It is recommended to use they/their as a pronoun to refer to someone whose gender is not specified:

Some people consider themselves neither male nor female, and some consider themselves both. Some people would not like to be referred to by the gender assigned to them when they were born. These people might ask you to refer to them as 'they' (singular).

Before we go through gender agreement, let's see what agreement is.
In English, agreement refers to the concept that the words in a sentence should be in harmony with one another. Take a look at the examples:

We can't say 'I is a doctor' or 'she am a nurse'. This is because English grammar demands that the verb and the subject agree in person.

In languages with grammatical gender, there should be agreement between nouns and their modifiers; let's see:

In English, we have the pronoun “they” and its relatives (them/their) which are gender inclusive and can be used with singular and plural meaning and for both male and female. So, the third-person plural pronoun is the same for all genders.

In most European languages, the pronouns are gendered like the pronouns in English, we have “él, ella” (he – she) and ellos, ellas (they (masculine) - they (feminine)) in Spanish, il (he), elle (she), ils (they masculine) and elles (they feminine) in French, and so on.
But not all languages have gendered pronouns, there are some languages without grammatical gender and some languages use the same word for “he” and “she” like ő in Hungarian or او (oo) in Persian, this will make the agreement of sentence elements easier.

In English, there are some proper nouns/titles/occupation names and some borrowed words which have a specific gender. For example, the names Andrew (masculine), Andrea (feminine), and Chris (neuter), or titles such as lady (feminine) and gentleman (masculine), some occupations like actor (masculine) and actress (feminine). There are also words like fiancé (masculine) and fiancée (feminine) which have entered English from the French language.

In English, almost all adjectives are gender neutral; but there are exceptions like blond (masculine), and blonde (feminine).

English determiners mostly have no gender, except the third person singular of possessive determiners. His/her/Its. For example:

In other European languages, the determiners are usually gender specific, for example, look at the French determiners:

In English, the verbs do not need to change in order to agree with the gender of the noun, but in some languages the verbs change to agree with the noun. For example, in Russian a male says, ‘Ya kupil knigu,' and a female says, 'Ya kupila knigu,' for ‘I bought a book’.

As you know, pronouns are used to replace nouns, personal pronouns are used so that we do not use the name of the person.

Nowadays, the gender of pronouns used for a person should not be assumed or guessed.
If a person's gender is unknown, you can simply use the third person singular “they/them”; it is grammatically correct and also respectful.
Neo-pronouns have not been officially added to the English language, but some dictionaries are including gender-neutral pronouns in their entries.

The use of neo-pronouns is like any other pronoun. Neo-pronouns can indicate the way someone perceives their gender, or that they just feel more comfortable being referred to using such pronouns.

The last one is called a nounself pronoun. Nounself pronoun users often choose pronouns based on objects or ideas that they have a strong personal connection to. For example:

Nounself pronouns may also be a reflection of one's gender identity. Non-binary gender identities that are outside of masculinity or femininity are called xenogenders. Like nounself pronouns, xenogenders can use objects or ideas as metaphors to describe how they feel about their gender. For example: