To avoid sexist language (michelle, 2013)
Gender-neutral language avoids constructions that are an unnecessary reinforcement of traditional stereotypes. Society is changing and language needs to reflect this and respect this. Working it all out is not easy, but it is possible. There are a number of ways of avoiding the use of generic male and female nouns and pronouns when we are referring to human beings, regardless their gender.
Gender and Names/Pronouns, Pluralizing. "Man" / "Mankind" and "He" were never neutral. Men were the reps of humanity. Women had no significant role except for child bearing and rearing, so men were considered the only intelligent human beings -- women were actually banned from education and thinking, banned from anything which was not being locked up serving others. Society is beginning to change, so we should make the effort of being sensitive to this chance. Use he or she, his or hers, his or her, him or her: "Each student is responsible for his or her learning," especially if you need to emphasize individuals. However, developments in English in the last decades have made it possible for us to say: "Each student is responsible for THEIR learning" when we are trying to avoid being sexist. The grammatical validity of this is disputed by some, but the fact remains that it is widely used. More examples: "Each student should hand in his writing assignment by Oct 10", use "Each student should hand in his or her writing assignment by Oct 10", or "Students should hand in their work by Oct 10". Instead of "A father should take care of his son", use "A parent should take care of his or her child" or "Parents should take good care of their children". Pluralizing: instead of "The student should request a form at the School Office", use "Students should request a form at the School Office."
Rewording: instead of "A pilot must keep his spacepod under control at all times; if he loses control, he must hit 'new game' immediately", use "A pilot must keep the spacepod under control at all times; if that control is lost, the pilot must hit 'new game' immediately".
Word choice: for example, by using people or humanity instead of man. Instead of "Early man used a system of gestures to communicate", say "Early humans used…" or "Early men and women…" Instead of "fireman", or even "fireperson" (it sounds a bit awkward) you can use "firefighter". Likewise, instead of "Policeman" or "policeperson", "police officer" sounds natural. Instead of "mailman" you can use "mailperson" or "postal worker". "Cleaning woman" should be referred to nowadays as "house cleaner" or "office cleaner", for instance. "Poet" can be either a woman or a man. [Where the gender is known, gender-specific items are also appropriate: "Bill Gates is a businessman" or "Nancy Pelosi is a congresswoman"] We also have "chair" instead of "chairperson" which would replace old "chairman" (when only men could be chairs. It was never a neutral form, but a masculine.)
Miscellaneous matters: There exist alternative spellings for words referring to gender (example: wimmin, herstory), but that is not suitable for academic writing or formal speech (yet?).
More information: The NCTE Guidelines for Gender-Fair Use of Language (The NCTE is the US American National Council of Teachers of English)