Read the Main Story: I'll Have What She's Having

A massive shift takes place across gender lines as we grow older. In New Passages I described the geometry of this shift as the "Sexual Diamond."

Males and females are very much alike for the first 10 years of life. We become radically differentiated at puberty and move to the farthest reaches of our oppositeness in our late 30s and early 40s -- the most distant poles of the Sexual Diamond. As we move into our 50s and beyond, both women and men take on many characteristics of their gender opposite, each becoming something of what the other used to be.

Anthropological studies, as well as empirical observation, tell us that men after 50 start to show greater interest in nurturing and being nurtured, in expressing themselves creatively or altruistically, and becoming more aware and appreciative of their surroundings. They remain identified with being male, but their need to prove themselves through sexual and aggressive conquest diminishes. They become more sentimental.

Women, across cultures, age psychologically in the reverse direction, becoming more aggressive, managerial and political. While they remain identified with being female, their focus is no longer diffused by caring for young children or the conflict between seduction and career achievement. Their tenderness and nurturing qualities become more broadly directed.

Around 50, men and women may run into a rather stark dysynchrony in their passages. As men's careers reach their peak and start winding down, either by choice or involuntarily, women's aspirations, often postponed by familial responsibilities, are likely to be revving up. One of the most dramatic changes in our social balance is the fact that so many women in their 40s and 50s today are holding down good jobs. There is nothing unusual about a midlife woman entrepreneur applying for a bank loan to start a new business or a nonprofit, or to go to graduate school.

Couples should not be surprised by a switch of polarities in marriage. But rather than the sexes' simply trading roles in middle life, men and women are freer to express both the masculine and feminine sides of their personalities. We have the chance to reach a point of harmony—the upper point of the Sexual Diamond -- where the tension of male-female differences relaxes at last.

The Sexual Diamond can be realized most easily in a mature couple who enjoy working together in a business or on a project, cause or major life endeavor. The worth of each one's contributions is affirmed from day to day. If a true complementarity is played out in the realm of work, it becomes more natural as the basis for compromise in the personal realm.

Gail Sheehy is perhaps America's leading writer on midlife transition. A bestselling author and cultural observer, she made history with the publication of Passages, later followed up by The Silent Passage, New Passages and Understanding Men's Passages.

This article is adapted from Sex and the Seasoned Woman: Pursuing the Passionate Life, by Gail Sheehy. Copyright © 2006 by Gail Sheehy. Reprinted by arrangement with the Random House Publishing Group. To learn more, visit http://www.seasonedwomansnetwork.com.