When you mean GENDER. C’mon, it’s a good word and only has one meaning. You also avoid unintentional malaprops (“Respondents have been broken down by sex”)
Why IMHO? I quite like sex. 
For what it’s worth, gender used to refer specifically to sex designations in language – for instance, in French, certain nouns are male, others female – and never to describe actual persons.
As the joke on The Benny Hill Show goes:
Benny (points at fly in soup): Le mouche! Le mouche!
Waiter: No, monsieur – la mouche!
Benny: You’ve got good eyesight!
I think gender started to take over that function of sex in the middle on the last century, 'cause people got tired of the smart remarks.
Which reminds me of another joke, from Futurama:
Fly: (at the “Smelloscope”): As long as you don’t ask me to smell Uranus!" (laughs)
Leela: I don’t get it.
Professor: Oh, astronomers got tired of hearing that old joke so they changed the planet’s name in 2052.
Fly: What do they call it now?
Professor: Urectum!
Actually, it has five meanings. Same as for sex.
From Merriam-Webster online:
Main Entry: gen·der
Pronunciation: 'jen-d&r
Function: noun
Etymology: Middle English gendre, from Middle French genre, gendre, from Latin gener-, genus birth, race, kind, gender – more at KIN
Date: 14th century
1 a : a subclass within a grammatical class (as noun, pronoun, adjective, or verb) of a language that is partly arbitrary but also partly based on distinguishable characteristics (as shape, social rank, manner of existence, or sex) and that determines agreement with and selection of other words or grammatical forms b : membership of a word or a grammatical form in such a subclass c : an inflectional form showing membership in such a subclass
2 a : SEX <the feminine gender> b : the behavioral, cultural, or psychological traits typically associated with one sex
Sex?
Austin Powers: Yes please! 
Well, in real life, apparently Ur-anus is not the proper way to say it anymore, as they have changed it to Urine-us. So much better, sounding like liquid waste product then your posterior.
If they really hate people making fun of the name, just rename it “Bob” or something.
Nobody’s tried “You’re-an-ass” yet. That one might slide by.
And the 23rd century slacker’s name is FRY.
This reminds me of when I almost gave my mother a heart attack…
I had just come back from my first day of kindergarten and asked “Mommy, what does ‘sex’ mean?” My mom nearly collapsed - she wasn’t expecting that talk for a good long while.
Then my all-so-clever dad stepped in and said, “When someone asks what ‘sex’ you are, they want to know if you’re a boy or a girl.”
Just as my mom calmed down, I said, “Oh, I knew those boys on the bus were lying. They said it’s when a boy and a girl get naked and lie on top of each other!”
true story!
Actually, “gender” was generally only used in the grammatical sense up until the 70s. “Sex” was considered appropriate when asking if you were male or female. However, people began getting tired of the jokes (those who think Austin Powers’s “Sex? Yes, please” is original, are sadly mistaken) and resurrected “gender.”
Isaac Asimov noted the issue, and suggested the original Greek “Ouranos” as a solution.
You don’t like “Uranus”? Consider that William Herschel, its discoverer (the first planet discovered since Classiocal times) originally wanted to name it “George”, a blatant attempt to suck up to the British monarch. Cooler heads prevailed, and they stuck another Olympian God’s name on it.
“Sex” didn’t even mean intercourse until the late 19th century. “Gender” means “kind,” so it’s isn’t specific enough etymologically. I say you shouldn’t call something a rectangle when you mean a square. “Gender” sounds too hopelessly anodyne to take seriously.
Shoot, and I thought this was going to be about that hopeless dipstick who used to sub for my sex-ed teacher. She wouldn’t let us use the word “sex” either, because it was dirty. We also couldn’t use the phrase “making love” without her snorting, “That’s not love, it’s lust.” Also on the list of stuff we couldn’t say in sex ed when she was subbing: f*ck, horny, orgasm, butt, vagina, and penis.
It’s really hard for kids to develop healthy, mature, responsible attitudes about lusting, wherein a man inserts his talleywhacker (yes, that’s the word she wanted us to use) into a woman’s opening. It’s even worse to ask such a person about the problems of putting a talleywhacker into someone’s tushie.
HA HA HA! That’s awesome CrazyCatLady!
Revenons a nos moutons… Gender absolutely means type. Most Americans are astonished to hear about Latin and German having 3 genders (masculine, feminine, and neuter), but I’ve heard there are languages with dozens of genders. All gender is used for in a language is classifying things. Sometimes gender separates sexes, sometimes inanimate objects, animals, et al.
Does anyone have an example of a language with more than 3 genders?
Must have been watching the Chinese version.
In Japanese, gender is not often clarified. For example, the sentence “Uchi e kaerimasu” could say I/he/she/it/we am/is/are going home.
In an anthropological sense, gender is different from sex. For example, my fiance is male, yet a woman. Although her biological sex is male, her cultural identity is as a woman.
In plenty of cultures, males or females will take on gender-related roles of the opposite sex. Biological males will dress like woman, do womanly duties and be considered women in the eyes of the society (and vice versa too). Gender (to me anyway and other anthropologists) is a social construction.
Gender? I hardly even know her!
Thank you, thank you. I won’t be here all week. Stiff your waitress.
I think you’re confused. You’re talking about pronoun (i/we/he/she/they) and verb form. Spanish has a tendancy to leave off pronouns, but they’re usually distinguished by the verb form which follows.
Gender is very different. In English we really don’t have gender markings for nouns; however, in the European languages I’ve studied (this whole definition probably doesn’t hold true for all languages) each noun has a gender. In German and Latin (and I’m sure others) that gender is sometimes neuter, but it’s a gender nonetheless.
The way a noun’s gender makes itself known (again, that I know of) is through the words equal to the English “a” and “the,” and also by suffixes added to adjectives and sometimes verbs associated with the noun. For example, the words for “pound” (both the measurement and the British monetary unit) and “book” in French are both “livre.” The former is feminine, the latter masculine, so to say “the pound” you say “la livre,” while “the book” is “le livre.”
Furthermore, most adjectives have an added letter “e” on the end if the noun they modify is feminine. To say “the English pound” one says “la livre anglaise,” while “the English book” is “le livre anglais.”