The undated handout photo shows the pipetting of a DNA solution. (Anonymous/ASSOCIATED PRESS)

Federal examiners have rejected patents for genetic screening tests because the applicants did not explore their effectiveness for different races, adding to the debate about whether race has scientific validity in modern DNA-based medicine.

Some geneticists, sociologists and bioethicists argue that “black,” “white,” “Asian” and “Hispanic” are antiquated categories that threaten to revive prejudices. Others, however, say that meaningful DNA variations can track racial lines and that ignoring them could deny many benefits of “personalized medicine,” which aims to develop tests and treatments tailored to a person’s genetic makeup.

“Just because of past misuse — in eugenics and during World War II — doesn’t mean we should bury our heads in the sand and shy away from valuable technology that could be leveraged to benefit all of humanity,” said Esteban Gonzalez Burchard, who studies biological variations among races at the University of California at San Francisco.

Officials at the U.S. Patent and Trademark Office say they do not require applicants to delineate how well any genetic tests — including those looking for an increased risk for diseases — work by race. A search of more than 3 million patents over the past 20 years found only 37 that included any reference to race, they said.

“We recognize that race is a fuzzy concept,” said Jennifer Rankin Byrne, a spokeswoman for the office. “It’s the genetic marker that’s important, not the racial group.”

Jonathan Kahn, a law professor at Hamline University in St. Paul, Minn., discovered the patent rejections when he began sifting through applications, prompted by a 2008 patent office presentation that raised the race issue.

“Constructions of race as genetic are not only scientifically flawed, they are socially dangerous, opening the door to new forms of discrimination or the misallocation of scarce resources needed to address real health disparities,” Kahn wrote in a report in the journal Nature Biotechnology in May.

One patent examiner, for example, rejected an application for a colorectal cancer risk test because it had been studied only among Hispanic men.

“The idea that Hispanic is a coherent genetic category is just silly,” Kahn said in a telephone interview. “It’s one of the most diverse — genetically and culturally and historically — populations you can find. The idea that it is genetically definable and distinct is just irresponsible.”

Similarly, in 2009, an examiner rejected a patent for a test for a propensity for prostate cancer because it did not specify the risk the variation posed among different races, Kahn found.

And in 2010, an examiner denied a patent for a test for a genetic marker for asthma and eczema because it was vetted only in whites and Asians.

The prostate cancer and asthma rulings were reversed on appeal. But the colorectal cancer applicant narrowed the application to win approval.

“There’s no telling how many people will just give in and use race in a way that the scientists clearly do not think is an appropriate way to use race,” Kahn said.

Just the fact that patent applications are including such information is disturbing, he and other critics say.

“This gives almost scientific legitimacy to the false categories of race — that somehow being white or being European is a strong category you can use in research,” said Troy Duster, who studies the racial implications of scientific research at New York University.

For decades, demagogues — and even some scientists — argued that racial groups were genetically distinct and, in some ways, biologically inferior or superior, justifying laws barring interracial marriage and other discriminatory practices.

Genetic predispositions — such as for sickle cell anemia, which occurs more frequently among African Americans, and Tay-Sachs disease, which is found more often in descendants of Ashkenazi Jews — clearly can pass down through generations. But as scientists developed modern tools of molecular biology, they produced ever more convincing evidence that genes vary as much among people who identify themselves as the same race as among groups segregated along traditional racial lines.

“What we are learning is that ancestry is really the key here,” said Charles N. Rotimi, director of the center for research on genomics and global health at the National Human Genome Research Institute. “The labels for race, at least as we currently use them, distort some of the things we want to understand in terms of ancestry.”

For example, although sickle cell anemia is more common among African Americans, the blood disorder is also rare in some parts of Africa and common in some predominantly Caucasian populations.

The ultimate goal of genetic-based personalized medicine is to match care to each patient’s genetic makeup, Rotimi and others say.

“You are truly going to be looking at that individual, whether black, white or Asian. It’s the individual’s genome that becomes important to their disease risk as opposed to their socially identified race or ethnicity,” said Vence L. Bonham Jr., an associate investigator at the institute, which is part of the National Institutes of Health.

Injecting race back into the mix carries myriad dangers, critics say. On a practical level, it may result in doctors using tests or treatments on one ethnic group and not another, denying people care based on the color of their skin.

“The danger is that it can have an effect on how pharmaceutical companies market their products and the views of physicians and patients,” said Pilar Ossorio, an associate professor of law and bioethics at the University of Wisconsin at Madison. “The result can be people are not getting the treatment they require.”

On a more disturbing level, it could fuel racism.

“It has the social consequence of making it seem that differences among groups are fundamentally biological,” said Barbara A. Koenig, a medical ethicist and anthropologist at the Mayo Clinic in Minnesota. “Inevitably, in our history, that leads back to the idea that one race is better than another.”

But others say that although race is far from perfect, some genetic variations with meaningful implications for health can be much more common among certain groups.

For example, the anti-seizure drug Tegretol produces a life-threatening skin rash more frequently among certain Asians than others; the best dose of the common blood thinner Warfarin varies by race and African Americans appear to be at an increased risk for kidney failure because they more often carry certain mutations.

“I don’t think race/ethnicity and personalized medicine are mutually exclusive,” said Neil Risch, a professor of human genetics and epidemiology at the University of California at San Francisco. “You can call it sociological, cultural — whatever. It’s all of the above. That doesn’t mean it’s devoid of genetic meaning.”

In fact, recent analyses have indicated that many common diseases probably are caused by genetic variations in different populations, making it crucial to assemble diverse databases, researchers said in an article published online July 13 by the journal Nature.

Two large genetic analyses published July 20 by the journals Nature and Nature Genetics found hundreds of genetic discrepancies between people of African American and European descent. And two papers published online Sunday by Nature Genetics found four unique genetic variations associated with asthma in people in Japan and people of African ancestry. Until scientists learn more about individual genetic predisposition, race provides a useful proxy, some say.

“I think there’s a healthy debate right now about the role of race in medicine,” said Noah A. Rosenberg, a professor of biology at Stanford University.