Q: Why do the NY Times and The New Yorker insist on hyphenating “teen-ager”?
A: Some words are like small construction projects. These compound terms start out life as different parts, but get mushed together (first with hyphens, then without) as they become more familiar.
For instance, the earliest published reference in the Oxford English Dictionary for the adjective “teenage” shows it as two words.
Here’s the citation from a 1921 article in a Canadian newspaper: “All ‘teen age’ girls of the city are cordially invited to attend the mass meeting to be held this evening.”
The next reference (from a 1935 issue of the journal American Speech) joins the two parts with a hyphen: “The dress is probably slinky and suitable for the teen-age group.”
Finally, a 1977 cite from the quarterly Daedalus has the term without a hyphen: “Society may wish to eliminate teenage street corner gangs, but this does not lead sociologists to write articles on the optimal techniques for eliminating such gangs.”
I’ve simplified this process somewhat. In the real world, English can be a messy business.
As for “teenager,” it’s hyphenated in the first published reference in the OED (from a 1941 issue of Popular Science Monthly): “I never knew teen-agers could be so serious.”
But less than two decades later, Kingsley Amis drops the hyphen in his comic novel Take a Girl Like You (1960): “Jenny thought to herself that here she was nearly twenty-one, and instead of having been a teenager all she had managed to do was spend a certain amount of time getting from the age of twelve to the age of twenty.”
Since then, the trend has been toward a hyphenless “teenager,” but some publications have been slower than others to get with the program.
The New Yorker is definitely a slowpoke, as witness this Nov. 3, 2008, headline: “Red Sex, Blue Sex / Why do so many evangelical teen-agers become pregnant?”
The New York Times, however, isn’t quite so poky. The latest Times stylebook (published in 1999) has “teenager” without a hyphen, though a search of the paper’s archive suggests that a few copy editors haven’t gotten the message.
[Update, April 30, 2019: The New Yorker continues to hyphenate “teen-age” and “teen-ager,” but the New York Times does not.]