Elizabeth Gregory teaches at the University of Houston and blogs on motherhood, birth timing, and the economics of women’s work at www.readymoms.com. She will be the guest on Chewing the Fat with Ophelia on Monday, March 23 at 10pm EST.

In the twentieth century two enormous framework changes radically altered the experience of being human:

1. Innovations in medicine and public health mean that first worlders today can expect to live an average 30 years longer in good health than did their counterparts a hundred years ago, and sometimes longer. Longevity has also expanded in the less developed world.
2. Since 1960, widely available hormonal birth control means that couples can choose if and when to have kids.

Together these two huge changes have allowed women across the globe to choose to structure their lives differently, and to have their children later than their mothers did. As a result, we’re all involved in the re-weaving of the social fabric that was patterned previously around the assumption that most women’s lives would be largely devoted to bearing and raising many children. This change has huge ripple effects for everybody.

While some women delay just a few years, expanding numbers wait much longer. In Ready: Why Women Are Embracing the New Later Motherhood, I explore the background to and the effects of this delay, looking specifically at women who start at or after 35, by birth or adoption. In 2007, 612,000 babies (one in seven) were born to mothers aged 35, and one in 13 first babies was born to a woman over 35.

Women report waiting for four basic reasons: education, establishing at work, finding the right partner, and self-development. The positive results include: higher lifetime wages, more clout to negotiate family-friendly schedules, peer marriages, more family focus, self-confidence, expanded cultural influence, longer lives. Drawbacks include: increased infertility (a real issue that has nonetheless been exaggerated in the media), and the sandwich effect (caring for elders and kids at once). Incorporating the voices of the more than 100 new later moms I interviewed, Ready looks in depth at the many dimensions of change—in business, family dynamics, fertility tech, public policy, health and our understanding of aging—affected by this trend.

I look forward to talking about all this tomorrow night when I’m the guest on Chewing the Fat with Ophelia. Please plan to listen and call in with your questions and comments!