FIRST came the generation gap, then the gender gap. Now comes the "family gap" - a wide separation in attitudes between married voters with children and those who are single or married without children.
When issues center on cultural values - such as abortion, working mothers, homosexual rights - the gap is widest, with families falling heavily on the conservative side, according to a Reader's Digest opinion poll released Tuesday.
The gender gap - a difference of as much as 10 points between men's and women's opinions on issues - was considered by political analysts to be a major influence in elections of the 1980s.
The family gap has even more potential to sway elections because it can exceed 20 percentage points, says Richard Wirthlin, the conservative pollster who conducted the survey.
"Instinctively, people may feel that when you're married and have children, you become more traditional and conservative. But until now, nobody had the data to back up that instinct, and it's amazing how wide the family gap is," says Mr. Wirthlin.
Political analysts agree that few, if any, polls ever measure family status in relation to political opinions. But they question whether the family gap is monolithic enough to have a concrete effect on elections.
"Common values do not necessarily mean that people will select common solutions," observes Don Kellerman, director of the Times Mirror Center for the People and the Press.
In 1983, CBS News pollster Martin Plissner saw evidence of a "marriage gap." In 1980 and 1982 election exit polls, he found married voters tended to be more conservative and Republican.
This gap, he says today, is much bigger than the gender gap and gets less attention. "Clearly this is the kind of information that a smart political campaign could exploit," he says.
Indeed, Wirthlin says the gap could easily make a difference in this year's three-way presidential race, in which a candidate could win with 30 to 40 percent of the vote.
The family gap cuts between the 92 million American adults over age 25 who are married with children (of any age) and the 34 million others who are single or married without children.
"The 92 million share a common set of cultural attitudes in sharp relief to other Americans," says Wirthlin, who adds: "In my view, this is a group that's up for grabs. An incremental shift here could add 9 million votes [to a candidate's total] ... and George Bush won by 7 million votes [in 1988].
"I don't see a magic bullet [for exploiting the gap], but a consistent appeal to the hopes and aspirations of this group [would be one way]," says Wirthlin.
He says none of the candidates so far has shown a sincere devotion to those hopes and aspirations, which he identifies largely as parents' concerns about the security of their children's future. That, he says, can include anything from safety from drug exposure to a deficit-free future.
Data suggest that age, race, religion, gender, income, and region are less a factor than family status when it comes to cultural values. Meanwhile, the family gap is less dominant on issues outside the cultural arena - the environment or the role of government in the economy, for example.
The family gap broke down this way on these cultural issues:
* Abortion. Adults married with children are split evenly - 48 percent pro-choice, 42 percent anti-abortion - while singles are far more likely to be pro-choice (72 percent).
* Working mothers. A 20-point gap separated families and singles on whether mothers should stay at home with small children when it is not a financial necessity to work. Just 53 percent of singles and 54 percent of marrieds without children approved of mothers staying home, while 74 percent of marrieds with children approved.
* Homosexual rights. Of voters without children, between 44 and 46 percent believe homosexuals have a right to marry. Just 28 percent of marrieds with children agree.