A recent report analyzing census records concluded that more women live alone than ever before in the U.S. Iowa State University Sociology Professor Susan Stewart, who’s written a book on step-families, says our image of the average household is unrealistic.

"I think we hold up this traditional homemaker – breadwinner model of the family as our standard traditional American family, but really that type of family existed for only a short time in our history, in the 1950s. Prior to that time, families were actually quite diverse: women worked, and there were high rates of widowhood and remarriage, and many different family forms existed."

In her view, step-families involve more than a narrow definition involving a remarriage. We tend to think of a widow or widower remarrying, or divorced people remarrying. She says step families also include families in which the partners are cohabitating without getting married and raising their children, some who gets married after having a child first, out of wedlock, and even adults whose parents remarry. "It’s very diverse these days," Stewart says.

For the first time, 51-percent of woman lived alone according to the most recent census data, outnumbering married woman. Stewart says it may be misleading, and the figure actually represents trends that are no surprise. "As a demographer, I know that we have an aging population," she says. More women are living to an old age and have lost their husbands. "It’s not that they’ve never been married, it’s that they’re not living with a husband currently.

Also, more young people are delaying marriage so the number of women who haven’t yet married — but someday will get married is higher. "But it’s still the case that 90-percent of men and women eventually marry," Stewart says, "and so this is not a trend that would indicate that people are less likely to marry." She says some would prefer to be married or living in a household with other people, but many enjoy living alone and prefer it that way.

Professor Susan Stewart’s study .