A new study suggests daughters usually work hard to care for their parents in old age while sons tend to do as little as possible.

Daughters provide an average of 12.3 hours of elderly parent care per month compared with 5.6 hours for sons, the American Sociological Association (ASA) reported. This means daughters twice as much time, or an average of seven hours longer with their elderly parents per month.

"Whereas the amount of elderly parent care daughters provide is associated with constraints they face, such as employment or childcare, sons' caregiving is associated only with the presence or absence of other helpers, such as sisters or a parent's spouse," said study author Angelina Grigoryeva, a doctoral candidate in sociology at Princeton University.

The findings also indicate gender is the most important factor in the amount of care siblings provide.

"Sons reduce their relative caregiving efforts when they have a sister, while daughters increase theirs when they have a brother," Grigoryeva said. "This suggests that sons pass on parent caregiving responsibilities to their sisters."

The new study relies on data from the 2004 data from the University of Michigan Health and Retirement Study, which surveys 26,000 Americans over the age of 50 every two years. The finding is significant because of the consequences of elder care on individuals.

"Numerous empirical studies report negative mental and physical health consequences, including a higher mortality rate, for people who provide care for elderly family members," Grigoryeva said. "In addition, these caregivers often have to balance elder care with employment, potentially resulting in career sacrifices and lower earnings. Providing care for elderly relatives can also impose significant financial burdens on caregivers in the form of direct expenses, as they often pay for goods and services for their care recipients.

Women have more elder care responsibilities, but have also been shown to suffer more consequences from it. These effects could have "potentially intensifying effects on a series of gender inequalities pertaining to health and economic well-being," Grigoryeva said.