At her annual visit, the patient’s doctor asks if she plans to continue having regular mammograms to screen for breast cancer lifestyle choices, and then reminds her that it’s been almost 10 years since her last colonoscopy.

She’s 76. Hmmm.

The patient’s age alone may be an argument against further mammogram appointments. The independent and influential U.S. Preventive Services Task Force, in its latest draft guidelines, recommends screening mammograms for women 40 to 74, but says “the current evidence is insufficient to assess the balance of benefits and harms of screening mammography in women age 75 years or older.”

Screening for colorectal cancer, with a colonoscopy or with a less invasive test, becomes similarly questionable at advanced ages. The task force gives it a C grade for those 76 to 85, meaning there’s “at least moderate certainty that the net benefit is small.” It should only be offered selectively, the guidelines say.

But what else is true about this hypothetical woman? Is she playing tennis twice a week? Does she have heart disease? Did her parents live well into their 90s? Does she smoke?

Any or all such factors affect her life expectancy, which in turn could make future cancer screenings either useful, pointless or actually harmful. The same considerations apply to an array of health decisions at older ages, including those involving drug regimens, surgeries, other treatments and screenings.

“It doesn’t make sense to draw these lines by age,” said Dr. Steven Woloshin, an internist and director of the Center for Medicine and Media at the Dartmouth Institute. “It’s age plus other factors that limit your life.”

Slowly, therefore, some medical associations and health advocacy groups have begun to shift their approaches, basing recommendations about tests and treatments on life expectancy rather than simply age.

“Life expectancy gives us more information than age alone,” said Dr. Sei Lee, a geriatrician at the University of California, San Francisco. “It leads to better decision making more often.”

Some recent task force recommendations already reflect this broader view. For older people undergoing lung cancer tests, for instance, the guidelines advise considering factors like smoking history and “a health problem that substantially limits life expectancy” in deciding when to discontinue screening.

The task force’s colorectal screening guidelines call for considering an older patient’s “health status (e.g., life expectancy, co-morbid conditions), prior screening status and individual preferences.”

The American College of Physicians similarly incorporates life expectancy into its prostate cancer screening guidelines; so does the American Cancer Society, in its guidelines for breast cancer screening for women over 55.

But how does that 76-year-old woman know how long she will live? How does anybody know?

A 75-year-old has an average life expectancy of 12 years. But when Dr. Eric Widera, a geriatrician at the University of California, San Francisco, analyzed census data from 2019, he found enormous variation.

The data shows that the least healthy 75-year-olds, those in the lowest 10 percent, were likely to die in about three years. Those in the top 10 percent would probably live for another 20 or so.

All these predictions are based on averages and can’t pinpoint life expectancy for individuals. But just as doctors constantly use risk calculators to decide, say, whether to prescribe drugs to prevent osteoporosis or heart disease, consumers can use online tools to get ballpark estimates.

For instance, Dr. Woloshin and his late wife and research partner, Dr. Lisa Schwartz, helped the National Cancer Institute develop the Know Your Chances calculator, which went online in 2015. Initially, it used age, sex and race (but only two, Black or white, because of limited data) to predict the odds of dying from specific common diseases and the odds of mortality overall over a span of five to 20 years.

The institute recently revised the calculator to add smoking status, a critical factor in life expectancy and one that, unlike the other criteria, users have some control over.

“Personal lifestyle choices are driven by priorities and fears, but objective information can help inform those decisions,” said Dr. Barnett Kramer, an oncologist who directed the institute’s Division of Cancer Prevention when it published the calculator.

He called it “an antidote to some of the fear-mongering campaigns that patients see all the time on television,” courtesy of drug manufacturers, medical organizations, advocacy groups and alarmist media reports. “The more information they can glean from these tables, the more they can arm themselves against health care lifestyle choices that don’t help them,” Dr. Kramer said. Unnecessary testing, he pointed out, can lead to overdiagnosis and overtreatment.

A number of health institutions and groups provide disease-specific online calculators. The American College of Cardiology offers a “risk estimator” for cardiovascular disease. A National Cancer Institute calculator assesses breast cancer risk, and Memorial Sloan Kettering Cancer Center provides one for lung cancer.

Calculators that look at single diseases, however, don’t usually compare the risks to those of mortality from other causes. “They don’t give you the context,” Dr. Woloshin said.

Probably the broadest online tool for estimating life expectancy in older adults is ePrognosis, developed in 2011 by Dr. Widera, Dr. Lee and several other geriatricians and researchers. Intended for use by health care professionals but also available to consumers, it offers about two dozen validated geriatric scales that estimate mortality and disability.

The calculators, some for patients living on their own and others for those in nursing homes or hospitals, incorporate considerable information about health history and current functional ability. Helpfully, there’s a “time to benefit” instrument that illustrates which screenings and interventions may remain useful at specific life expectancies.

Consider our hypothetical 76-year-old. If she’s a healthy never-smoker who is experiencing no problems with daily activities and is able, among other things, to walk a quarter mile without difficulty, a mortality scale on ePrognosis shows that her extended life expectancy makes mammography a reasonable choice, regardless of what age guidelines say.

“The risk of just using age as a cutoff means we’re sometimes undertreating” very healthy seniors, Dr. Widera said.

If she’s a former smoker with lung disease, diabetes and limited mobility, on the other hand, the calculator indicates that while she probably should continue taking a statin, she can end breast cancer screening.

“Competing mortality” — the chance that another illness will cause her death before the one being screened for — means that she will probably not live long enough to see a benefit.

Of course, patients will continue to make decisions of their own. Life expectancy is a guide, not a limit on medical care. Some older people don’t ever want to stop screenings, even when the data shows they’re no longer helpful.

And some have exactly zero interest in discussing their life expectancy; so do some of their doctors. Either party can over- or underestimate risks and benefits.

“Patients simply will say, ‘I had a great-uncle who lived to 103,’” Dr. Kramer recalled. “Or if you tell someone, ‘Your chances of long-term survival are one in 1,000,’ a strong psychological mechanism leads people to say, ‘Oh thank God, I thought it was hopeless.’ I saw it all the time.”

But for those seeking to make health decisions on evidence-based calculations, the online tools provide valuable context beyond age alone. Considering projected life expectancy, “You’ll know what to focus on, as opposed to being frightened by whatever’s in the news that day,” Dr. Woloshin said. “It anchors you.”

The developers want patients to discuss these predictions with their medical providers, however, and caution against making decisions without their involvement.

“This is meant to be a jumping-off point” for conversations, Dr. Woloshin said. “It’s possible to make much more informed decisions — but you need some help.”

Cheri Pies, a professor of public health who broke barriers with her landmark 1985 book, “Considering Parenthood: A Workbook for Lesbians,” a bible of the “gayby boom” of the 1980s and beyond, died on July 4 at her home in Berkeley, Calif. She was 73.

The cause was cancer, said her wife, Melina Linder.

Later in life, Dr. Pies (her first name was pronounced “Sherry”) became a pioneering researcher and professor at the University of California, Berkeley School of Public Health, investigating the effects of economic and racial inequality in matters like infant mortality and health over generations.

But she made her name decades before her turn toward academia with her groundbreaking book. That journey began in the 1970s, when Dr. Pies was working as a health educator for Planned Parenthood, counseling straight women considering motherhood.

Her focus began to shift in 1978, after her female partner adopted a daughter. At that time, the concept of openly gay parents was still mostly unheard-of in the culture at large.

Just that year, New York became the first state to say it would not reject applications for adoption solely on the basis of homosexuality. A year later, a gay couple in California broke barriers as the first known to jointly adopt a child.

Dr. Pies was struck by the lack of support available to same-sex parents, as well as the lack of basic information about the unique challenges they face. She began running workshops in her home in Oakland, Calif., advertising them with fliers in women’s bookshops and other places where lesbians gathered.

By the early 1980s, word of her work had spread beyond the Bay Area, and she was bombarded with letters and phone calls from lesbians around the country. In response, Dr. Pies compiled her teachings and experiences into a book. “Considering Parenthood: A Workbook for Lesbians,” published by the lesbian feminist press Spinsters Ink, provided practical advice on a wide range of topics, including the use of sperm donors, legal issues surrounding adoption, and ways to build a support network.

The book, which appeared 30 years before same-sex marriage was legalized nationally, opened the floodgates for countless other books about L.G.B.T.Q. parenthood.

“She was absolutely a pioneer, and those of us who came later built on her work,” G. Dorsey Green, a psychologist and author of “The Lesbian Parenting Book” (with D. Merilee Clunis, 2003), was quoted as saying in an obituary about Dr. Pies on Mombian, a website for lesbian parents. “I would recommend her book to clients. That was when lesbian couples were just starting to think about having children as out lesbians. Cheri started that conversation.”

Dr. Pies, who earned a master’s degree in social work from Boston University in 1976, would eventually turn to academia, receiving another master’s degree, in maternal and child health, from Berkeley in 1985 and a doctorate in health education there in 1993.

She was serving as the director of family, maternal and child health programs for Contra Costa County, which borders Berkeley and Oakland, when she heard a lecture in 2003 by Dr. Michael C. Lu, who would go on to become the dean of the Berkeley School of Public Health.

Dr. Lu spoke about a concept called life course theory, which centers on the idea that the social and economic conditions at each stage in life, starting with infancy, can have powerful, lasting effects over generations. “What surrounds us shapes us,” Dr. Pies explained in a 2014 lecture at the University of Alabama at Birmingham. “Some people would say your ZIP code is more important than your genetic code.”

At Berkeley, Dr. Pies would eventually collaborate with Dr. Lu and others to create the Best Babies Zone initiative, a groundbreaking program that would study — and, ideally, improve — health conditions in economically challenged neighborhoods around the country.

In 2012, she became the program’s principal investigator, after Dr. Lu took a post in the Obama administration. The initiative included home health visits and work with community leaders to create parent-child play groups, improve park safety and enhance job-skills training. It began in Oakland, New Orleans and Cincinnati and had spread to six other cities by 2017, the year Dr. Pies retired from Berkeley. The program is still active today.

“There are people doing large-scale policy work around structural racism, trying to change policy and practice,” Dr. Pies said in an interview published on the Berkeley School of Public Health website in April. “Best Babies Zone is at the other end of the spectrum, going small-scale to make change for people who can’t wait for policy change to happen.”

The high incidence of low birth weight and sudden infant death syndrome in such communities was a focus of the program. “Babies are the canary in the mine,” Dr. Pies said in her University of Alabama speech. “If babies aren’t born healthy, you know that something isn’t right in the community.”

Cheramy Anne Pies was born on Nov. 26, 1949, in Los Angeles, the second of three daughters of Morris Pies, a physician, and Doris (Naboshek) Pies, a nurse. (She later changed her name to Cheri.)

Growing up in Encino, in the San Fernando Valley, the outgoing, ebullient Cheri was a fan of movies, particularly musicals like “My Fair Lady,” and got an early taste of the medical profession working as a receptionist in her father’s office.

After graduating from nearby Birmingham High School, she enrolled at Berkeley in 1967, where she earned a bachelor’s degree in social science in 1971.

Berkeley at the time was a cauldron of Vietnam War-era political passions, after the Free Speech Movement protests that rocked the campus starting in 1964. “Even though I was not actively engaged in it, I was certainly exposed to the politics of it,” she later said of the movement.

In addition to her wife, Dr. Pies is survived by her sisters, Lois Goldberg and Stacy Pies.

She would eventually channel Berkeley’s 1960s spirit of activism as an author and professor, working to improve the lives of openly lesbian parents of the 1980s and beyond — whose numbers swelled so quickly that by 1996, Newsweek magazine would report that an estimated six million to 14 million children in the United States had at least one gay parent.

“Adoption agencies report more and more inquiries from prospective parents — especially men — who identify themselves as gay,” the article read, “and sperm banks say they’re in the midst of what some call a ‘gayby boom’ propelled by lesbians.”

Many of that generation would acknowledge their debt to Dr. Pies for the rest of her life, Ms. Linder said in a phone interview: “Cheri and I could be anywhere in the world — on a hike in New Zealand or just walking in the Berkeley Hills — and people would see her and stop to thank her, saying how Ben or Alice or whoever would not be in their life were it not for Cheri.”