Now there’s scientific research to back up the advice recording artist John Mayer gives in his hit song “Daughters.”

In a presentation today at the Annual Meeting of the American Sociological Association in San Francisco, a researcher from Princeton University explained that daughters tend to provide their elderly parents with as much care as they can. Sons, meanwhile, do as little as possible.

Angelina Grigoryeva, a doctoral candidate in sociology, told Healthline that daughters provide elderly parents with an average of 12.3 hours of care per month. Sons give less than half that with only 5.6 hours.

In her paper, Grigoryeva argues that gender is a bigger determinant of caregiving than birth order or how much money children make.

Mayer, popular among baby boomers, sings, “Fathers, be good to your daughters/ Daughters will love like you do/ Girls become lovers, who turn into mothers/ So mothers be good to your daughters, too.”

It might be easy to assume that daughters provide more care because of an innate maternal instinct. But Grigoryeva’s work suggests there’s much more going on, from gender roles that have become cemented in our society to discrimination in the workplace.

“It’s hard to say what comes first, whether daughters start providing care because of the labor market, or because they’re daughters and they’re expected to do it,” Grigoryeva said. “It can go both ways. There is definitely an association, but association is not causation.”

Women Already at an Economic Disadvantage

Grigoryeva analyzed data from the 2004 University of Michigan Health and Retirement Study, which she called the “gold standard in aging research.” The study surveys more than 26,000 people for a nationally representative sample every two years.

Related News: Millions of Caregivers Offer Billions in Support »

The survey asks retired people where they get help doing household tasks. It collects information about several dynamics related to parent-child relationships, including financial exchanges.

Although she used numbers a decade old, she said she has since reviewed 2010 results as well and found them to be very similar. In fact, she said she looked at numbers as far back as the 1990s and saw no major changes over time in terms of how much care sons and daughters provide.

As it is, women are stigmatized in the workplace. Research shows that companies often are leery of hiring mothers for fear of issues related to child care. This is often called the “motherhood penalty.” Many women who take time off after childbirth have a difficult time finding work when they are ready to re-enter the workforce.

The survey showed that the less work daughters provide through employment, the more help they tend to offer their parents.

With more women than ever entering the workforce and the baby boomer generation nearing retirement age, a showdown over inequality in providing care to parents is imminent. Dementia also is becoming a national epidemic, with many seniors requiring expensive 24-hour care.

Close to 11 million seniors in 2006 needed help with at least one task associated with independent living, according to Grigoryeva’s paper. Most do not qualify for subsidized assistance and cannot afford to hire help on their own.

Parents More Time-Consuming than Children

Grigoryeva said research shows some people spend more time taking care of parents than children.

The study found that often, children funnel their money toward the care of a parent. Surprisingly, the amount of care children provide goes up as expenditures go up. This may be because children want to supervise the work of paid caregivers.

Not only do caregivers take a financial hit to cover hired help and lost wages due to an inability to work full time, but caregiving also takes a mental and physical toll on children.

Brenda Klauer of Bettendorf, Iowa, is one of those women who did not “reboot her career,” as she put it, after having children. Since she works part time, she has more time to spend helping her elderly mother.

She said her brother did the work for a while, but she felt it wasn’t being done very well, and her brother implied that it was a hassle. It was easier to just do it herself, she said. Her husband supported her in that decision.

Grigoryeva’s research shows that when an elderly person’s son has a sister, the amount of care he otherwise would have provided drops.

Klauer said she found Grigoryeva’s research mostly affirming. However, Grigoryeva’s study claims that married couples tend to focus individually on their own parents and not help much with caring for their in-laws.

Read More: Caregivers for Elderly Parents Are the New 'Working Moms' »

Klauer said her husband helps a lot with her mother. Klauer and her husband intend to move her mother in with them when she can no longer live independently.

Some Sons Do Step Up to the Plate

Sons do step up when they have to, Grigoryeva’s work shows. But it is usually is when there is no sister in the picture.

Doug Perkins of Andalusia, Illinois, takes issue with the paper’s claim that daughters do much more than sons to care for their parents.

Perkins has cared for his mother, who has Alzheimer’s disease, for many years. She was in a care facility for several years, but it took all of her life savings. Perkins cared for his stepfather during that time, too. He has since passed away.

Several years ago, Perkins moved his mother in with him and his partner, who also helps a great deal. Perkins recently returned to work because he said he was going “stir crazy.” Perkins and his partner hired a full-time nurse to help with his mother, and she also receives in-home hospice care.

Meanwhile, Perkins’ mother-in-law has been diagnosed with cancer. In addition to caring for his mother, Perkins and his partner now assist her, too.

Grigoryeva said her research offers a “snapshot” of the amount of care elderly parents receive from their children. It does not look at how levels of care may change over time.

For example, it does not account for increased caregiving needs if a parent develops dementia and needs 24-hour care. She said she would like to take a look at that in her next research paper.

The 20 Best Alzheimer's Blogs of 2014 »