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Women who leave it late to embrace motherhood are often criticised for gambling with their fertility and risking their own and their baby's health. But now a leading academic says it's better for many women to delay getting pregnant.
Professor Elizabeth Gregory says older mothers are financially secure and happy to put their careers on hold while they bring up baby and are more likely than younger first-time mothers to be in stable relationships.
They also live longer.
Her new book will be welcome news for pregnant Jennifer Lopez, 38, and Halle Berry, 41, who just are the latest to join the growing club of celebrity older first-time mothers that includes Desperate Housewives' Marcia Cross, who had twins recently at 44, and Salma Hayek, 41, who became a mother in March.
These women have been worried that they are risking both their health and the welfare of the babies by choosing to start families later.
But that view is challenged in Gregory's book, due out in January, Ready: Why Women Are Embracing the New Later Motherhood.
"I have found an overwhelming number and range of reasons why what I have termed the "new later mothers" are absolutely right to delay motherhood,' said Gregory, director of the Women's Studies Programme at the University of Houston.
"For one thing, they feel ready to focus on family rather than trying to juggle priorities because they have achieved many of their personal and career goals.
"They also have more financial power, because new later mothers have established careers and higher salaries. They also have greater self-confidence, because they have more career experience and their management skills often translate directly into managing a household and advocating for their children.'
In addition, said Gregory, these mothers had an unusually high marriage rate. Almost 85 per cent were married, but older single first-time mothers tend to have a more stable support network than their younger counterparts.
Gregory's book is one of a number of new studies in praise of older mothers. One study, of 4300 older mothers published in the Journal of Epidemiology and Community Health, found that women who delay starting a family until later are more likely to have brighter, well-behaved children.
The explanation, the authors said, could be both biological - older mothers make sure they have better nutrition during pregnancy - and social: they may have a more established home life that is more conducive to learning.
But there could be hidden costs to later motherhood. For example, there is likely to be an increase in the number of children who will lose their parents at a younger age, while their children will not experience having grandparents.
"There is evidence that new later mothers live longer than those who start their families earlier,' said Gregory, pointing to a study from the Population Research Centre at the University of Texas that indicates a woman's reproductive peak is not the best time to start making babies.
John Mirowsky, author of the study and a member of the National Institute of Health's scientific review panel on human development and ageing, believes the prime age for childbearing, in terms of maternal health and longevity, lies between 34 and 40.
His study is backed by others, including the New England Centenarian Study led by Thomas Perls, which found that women who gave birth after 40 were four times more likely to live to be 100 or more than women in the general population.
Nevertheless, Gregory believes the best argument for later motherhood is an emotional one.
"For the women I spoke with, and for their families, the new later motherhood experience has had overwhelmingly positive effects," she said. "They enjoy motherhood immensely and most combine it with satisfying work. These women feel they've come to motherhood prepared and that their children, their marriages, their careers and their sanity are the better for it."
