RALEIGH, N.C. - Stay-at-home moms may have been right all along when their maternal instincts told them they're best equipped to care for their children.

A new study from North Carolina State University concludes that children of mothers who work outside the home have a significantly higher risk of health problems, accidents and injuries.

The study found that kids of working moms have a 200 percent increase in the risk of experiencing overnight hospitalizations, asthma episodes, and injuries or poisonings.

Parenting is an intensely emotional subject that leads to feelings of guilt, inadequacy and - just as often - a sense of superiority among parents, particularly among moms who handle the bulk of child-rearing duties.

The so-called mommy wars have heated up in recent years as the numbers of women with children under age 18 who are in the work force has risen to more than 75 percent.

Dr. Melinda Morrill, the N.C. State economics professor who authored the study, warned against making sweeping moral judgments against moms who work outside the home. But she noted that parenting choices involve trade-offs that must be acknowledged.

"Maternal employment imposes a burden on a mother's time and may result in the poorer supervision or care of her children," Morrill's study says. "A child's health is at least partially a function of time-intensive activities such as healthy meal preparation and house cleaning."

Morrill's research looked at 89,000 kids ages 7 to 17, examining 20 years of data from the federal National Health Interview Survey.

Morrill's research runs counter to previous studies that have shown that children of working moms have improved health. Those studies have said that kids of working moms benefit from increased income, from better health insurance options and from a boost in the mother's self-esteem.

But Morrill concluded that the earlier studies confused causes with effects, overlooking the fact that mothers of children with special needs or chronic health problems were often unable to work outside the home. In these situations, electing to become a stay-at-home mom did not cause or exacerbate the child's health problems; rather, the child's problems led to the mother's decision not to work outside the home.

Her study said parenting choices are based on complex variables, but in some cases a stay-at-home mom and a working mom may have very different temperaments and talents.

"A mother's decision to work could reflect underlying (and unobserved) ability, skills or preferences, so that a mother that works may be different in important ways from a mother that does not work," Morrill wrote.