It's long been known that high-powered careers can hamper or delay women's plans to have children. But a new study suggests the challenges loom especially large for women of Generation X.

A full 43% of skilled white-collar Gen X women, ages 33 to 46 years old, haven't yet had children based on a study of 2,952 college-educated white-collar workers released last week.

The study conducted for the Center for Work-Life Policy, by Knowledge Networks, suggests the pressures imposed by demanding work schedules of 60 hours or more a week, along with strong career ambitions, heavy debt loads and the sluggish economy, are among the reasons, according to the Center. The conclusions are based on a survey, focus-group discussions and one-on-one interviews.

Of course, women in general are starting families later than they did in the past, using the extra years to finish their education or build a career, the Census Bureau says. The average age of U.S. women giving birth for the first time rose 3.6 years between 1970 and 2006 to 25 years, according to the National Center for Health Statistics. More recently, the recession and sluggish job market have also played a role in people's delaying plans to start a family, as we have posted before.

The childbearing patterns of these white-collar workers depart from those of the population as a whole. Only 18.8% to 29.7% of women ages 30 to 44 years haven't yet had children, based on the most closely comparable and most recent Census Bureau data from 2010.

That suggests workplace pressures may indeed be having an impact. Also, Gen-Xers, born between 1965 and 1978, shouldered a heavier burden of student loans after college, compared with preceding generations, and as young adults they experienced several boom-and-bust cycles, as well as a severe housing slump. All of these factors may have made starting a family and providing such basics as housing and education seem more difficult.

"Searching for a balance between work demands and personal obligations leaves them overworked, overstressed and overstretched," the study says.

As a result of the pressures, however, Gen Xers are also more resilient, researchers say. They set lofty goals for themselves; of those surveyed, 75% of Gen-X women surveyed and 72% of Gen-X men describe themselves as ambitious. But many are frustrated in their career ambitions by older baby boomers ahead of them in the management pipeline, many of whom can't afford to retire. Nearly half of Gen-Xers feel stalled in their careers, the study says. Also, 43% say their ability to repay student loans plays an important role in their career choices.

The finding calls to mind child-bearing patterns in the 1970s and 1980s among older members of the baby-boom generation, some of whom passed up having children because of the pressures of executive jobs. One 1982 study found only 39% of top female executives had children. That percentage had risen to 57% by the early 1990s, however, as combining motherhood and executive careers became more accepted and common.

Readers, do you think demanding jobs keep women from having kids? Or cause them to delay child-bearing longer? Are student loans a major factor? Have workload, career ambitions or debt played a role in your decisions about starting a family?