soccer mom
n. A white, suburban woman who is married and has children.
Examples
1996
One last word before we file The Year of the Soccer Mom into the political calendar of cliches.

Somewhere along the way, the stressed-out, minivan-driving juggler of lives and roles was awarded the title of MVP in the competition for voters. She became the icon of 1996, nearly running over the Angry White Male of 1994 in her new Dodge Caravan.

But in politics, as in soccer, you have to use your head. A trip through the postelection world is a reminder that her role was a touch inflated. Suburban, married moms with kids at home were never more than 6 percent of the voters. Gary Langer at the ABC News Polling Unit calls them simply the "group du jour." He fairly sputters at the idea that they could swing anything but a headline.
—Ellen Goodman, “Meet the worried woman,” The Boston Globe, November 10, 1996
1982
A judge has found a husband guilty of looting $3,150 from the treasury of the Soccer Moms booster club in Ludlow headed by his wife. Joseph Decosta, 34, of Ludlow, was found guilty Wednesday and ordered to spend a month in jail and make restitution to the club, which runs candy sales and the like to raise money for soccer games for 400 boys and girls ages 6 to 19.
—The Associated Press, October 14, October 14, 1982
1973 (earliest)
My letter is in the defence of soccer. It is about time soccer leagues got some publicity.
Soccer Mom, “In defence of soccer,” The Argus (Fremont, California), September 21, 1973
Notes
This term's arc through the media is interesting. From its earliest citation through to the end of 1989, soccer mom appeared six times in the media. Here are the annual numbers through 1996:

1990 — 4
1991 — 8
1992 — 5
1993 — 10
1994 — 19
1995 — 35
1996 — 1,150

That impressive spike in 1996 was due to the incredible amount of ink devoted to the soccer mom demographic in the U.S. presidential election of that year.