Gender
In English there are masculine, feminine, common or dual (m or f), and neuter (sexless) genders.
Gender is expressed by inflection only in personal pronouns, and only in the 3rd person, singular he, she, it; the 1st and 2nd person forms I, we, and you are common gender, while the 3rd person plural form they is either common gender or neuter (the people ... they, the boats ... they).
Relative and interrogative pronouns and some other pronouns inflectionally express a related category of animacy (animate/inanimate): who, whom vs. what, which, somebody/one vs. something, anybody/one vs. anything.
Distinctions of animacy are variable, but commonly speakers distinguish between human beings and higher animals (the {woman, dog} who ...) and lower animals and inanimate things (the {ant, stone} which ...).