Do you consider the term: mankind to be sexist . . . whereas the word: humankind is more appropriate, accurate, and inclusive?
The term "humankind" certainly is not inappropriately discriminatory, as to both age (regarding non-adult children) and gender (regarding females) of non-lower-lifeform persons having souls and eternal destinies in Heaven or Hell.
Admittedly, the term: mankind is much more common, has less syllables for those too lazy to utter greater-than-one-syllable words, is rigidly and legalistically "traditional," whereas the replacement term: humankind is presumed by many to be kind of weird and certainly rather unusual.
English semantics of most Bible translations set and impose the lamentable and inaccurate standard by imposition of the word: "man" for both female humans and child humans.
For example, consider the RSV rendition of the following Scripture verses:
Matthew 4:3 And the tempter came and said to [Him], "IF (not: "since") you are the Son of God, command these stones to become loaves of bread."
Matthew 4:4 But [He] answered, "It is written: 'Man shall not live by bread alone, but by every word that proceeds from the mouth of God.'"
First Corinthians 15:21 For as by a man came death, by a man has come also the resurrection of the dead.
First Corinthians 15:22 For as in Adam all die, so also in Christ shall all be made alive.
Big deal? So what? Why rock the boat, and possibly cause divisive dissension, disruptive confusion, disunity, and expensive obsolescence and replacement - by having the word "humankind" substitute for "mankind?"
Besides, Adam (according to the Greek Text of the New Testament) is specifically named with Greek letters, thus purported to be at fault for everyone from him onward (including Adam himself) dying . . . even though the Divinely-inspired author of First Corinthians thankfully did place the blame on the inferior gender who should have been blamed for starting death (of herself, and Adam, and everyone else thereafter):
First Timothy 2:11 Let a woman learn in silence with all subjection.
12 I allow no woman to teach or to have authority over men; she is to keep silent.
13 because Adam was formed first, then Eve;
14 and Adam was not deceived, but the woman was deceived and became a transgressor.
15 Yet woman will be saved by bearing, better yet: birthing (according to "as woman was made from man, so man is now born of woman . . ." of First Corinthians 11:12, occasionally-male) children (not by committing abortion-homicide, sterilizing themselves with "birth"-control anti-pregnancy whatevers, or semen-wasted non-vaginal coitus interruptus), if she continues in faith and love and holiness, with sensibility.
Not only does the term mankind exclude females and children, but it is intrinsically wrong as the the actual and exact meaning of the Greek word behind such "man" passages.
The Greek word for "man" in Matthew 4:4 is: anthr(o)pos [pronounced: an-THROW-pahss, not: an-THROP-ahss . . . being that the (o) signifies the Greek letter omega, contrasted with the Greek letter "o" for omicron]. Clearly, the English term anthropos is where we get our word: "anthropology" which is the study of humankind -- not merely mankind nor womankind nor childkind.
The Greek word anthr(o)pou is basically the same root word (the slight ending change of it from os to ou makes no difference as to age nor gender) in First Corinthians 15:21 shown above.
So the precise meaning of Matthew 4:4 is that humans shall not live by bread alone, and the precise meaning of First Corinthians 15:21 is that by a human came death, and by a human has also come the resurrection of the dead.
So, whenever you come upon any "man" word in the New Testament, keep in mind that the actual Greek-Text word meaning usually is: human and neither exclusively "male" nor "female" nor "child."
Some words, of course, are gender-specific, as to understandably-different-lettered (as in English) Greek words for "brother" and "sister," "father" and "mother," "husband" and "wife." For example, the word for "wife" in the Greek Text (as for example in the "if any man is blameless, the husband of one wife, and his children are believers . . . of Titus 1:6) is gynaikos from where we get the English word "gynecology" which obviously does not refer in any way at any time to male humans and thus is never equivalent nor synonymous.
Sorry, all you transsexuals and transgendered. The basic Greek-Text wording and correct semantical understanding thereof within and of the Bible is against you, irrevocable and irrefutable, and your homosexuality-related inclination and consequences are elaborated in Leviticus 20:13, Romans 1:18-28, and First Corinthians 6:9 with the Greek-Text words: malakoi [effeminate] and arsenokoitai [sodomites] as to some of those not and never inheriting the kingdom (not "queendom") of God.