Gender is not important enough for us to be constantly emphasizing it in language. If you disagree, you may find Hofstadter's Person Paper on Purity in Language convincing. How can we get gender out of our language?

Over the last generation we have made some progress in this direction. The title 'Ms.' is now widely accepted, though it has not supplanted 'Mrs./Miss'. 'Firefighter' has almost caught up to 'fireman'. People my age will commonly use singular 'they' in situations that people my parents age find a little peculiar and 'themself' is on the rise (though 'singular they' is not new). Is there anything I can easily do to move us further?

Pronouns are what seem the weirdest to me about gendered language. Why specify he/she with every reference? While there have been many attempts to create new gender neutral pronouns, they haven't really spread. I think the strongest horse in this race is singular they, and I see several gradations in its usage, which I've organized from most to least acceptable to my ear:

unspecific ungendered:

• Someone has their head screwed on wrong.
• With the door left unlocked like that, anyone could just walk right in and make themself at home!
• Everyone must bring their own fork.
• What should you wear if your boss asks you to dinner at their house?
• You can tell a good worker by whether they keep their desk clean.

specific unknown-gender ungendered:

• I hear you have a new lab partner; what are they like?
• Who's the person who does booking for the Knoxville dance, and what's their email?
• I bet the cop who pulled you over was just trying to meet their quota.

unspecific implied-gendered:

• Any Bryn-Mawr student found to be cheating shall have their grade invalidated.
• If someone asks for an epidural while giving birth, even if they previously were dead set against the idea, you still give them one.

specific unknown-gender ungendered:

• With your baby dressed in yellow I can't tell if they're a boy or a girl.
• That genderqueer person sure loves their polka-dot suits.

specific known-gender ungendered:

• My new boss is such an idiot! I don't understand how they managed to get through the hiring process.
• The person who gave me a ride home from the dance last night doesn't take care of their car.
• My kid told me they're not going to go to school any more; we'll see about that!

unspecific gendered:

• I just love to see a hunk with their shirt off.
• When a woman's life is on the line, they do what they have to do.
• It's kind of annoying having so many friends named 'David'. The next time I see one of them I'm going to ask if they'd mind me calling them 'Dave'.
• Whenever I meet a cute boy contra dancing I friend them on Facebook.

specific gendered:

• Why do you think the old man who lived on the corner shot themself?
• Look at that careless woman spilling beer all over their kid!
• While I know it's hard for Marty as a single father, there's no call for them to yell at their kids like that.
• I can't deal with how forgetful Deborah is! Just this morning they left their cellphone on the train.

I suspect most readers will be pretty much fine with the first one and completely reject the last one. For me I'm mostly fine up until the "unspecific gendered" referent, though the previous category can be a little iffy. But that there is a gradation suggests a strategy for increasing the range of acceptable usage for singular they: try to move a little further along the gradation than you feel totally comfortable, and perhaps it will start sounding more reasonable to you and the people around you. Eventually we end up with an ungendered pronoun we can use in all circumstances.

(I do worry about spending my budget for weirdness on the wrong things, like using unusual pronouns or spending a lot of time barefoot. I also worry about the mental overhead of language changes. So I'm going to try not to overdo this.)

Update 2012-08-07: added the "specific unknown-gender ungendered" category.

Update 2014-08-06: I just talked to an intern at work who doesn't hear anything wrong with "Mike needs to check their code in" where "their" refers back to "Mike". This coworker's model of "they" is "it's sometimes singular and sometimes plural, depending on context." This is good.

Update 2014-11-17: #3 and #4 of "unspecific gendered" now sound completely fine with me.