He could use animals or a computer model, but he says nothing else provides results that are as accurate.
"If we want to study a process, it's best to study the real thing," said Pandey, who has used fetal tissue for more than a decade to better understand pancreatic and breast cancers and leukemia. "Models can be insufficient in mimicking what we want to study. Even today we don't understand all the biological processes. We can make a little bit of skin in the lab or cartilage, but not organs. For that, there is more complicated interplay."
Scientists like Pandey have used tissue from aborted fetuses in their research for years, but debate over the practice has re-emerged after Planned Parenthood was recently accused by anti-abortion activists of profiting from the practice.
Planned Parenthood has said it charges fees to cover its costs but has denied that it makes money. That hasn't silenced the concerns of critics, who struggle with the morality of using tissue they say was derived from taking a life through abortion.
Many scientists say that fetal tissue has led to crucial medical advancements that have saved many lives and has the potential to lead to even more groundbreaking research. Such cells have been used to develop vaccines for chicken pox, rabies and hepatitis A. Eye tissue from fetuses has been used in studies seeking ways to prevent vision loss, as well as those examining remedies for degenerative muscle diseases.
Fetal cells are seen as ideal research specimens because they grow and divide rapidly, allowing scientists to watch the process and get a better understanding of how an organ or tumor develops out of a cell.
J. Michael Bowers also has used fetal tissue, in studies on brain development. He finds that animals don't make the best research subjects. Rats can't speak, so they wouldn't provide the most accurate picture for his work — looking at the link between a specific gene, brain development and language, the University of Maryland School of Medicine researcher said.
Bowers used fetal tissue while doing research at the University of Texas Southwestern Medical Center. He received an $88,000 grant from the National Institutes of Health under its fetal tissue funding program for his most recent study, to look at gender differences in brain development. That research could include the use of cells derived from fetal brains, helping to answer why some mental disorders are more common in men or women.
"Having something that is human to address a human disorder is second to none," Bowers said. "It is an immensely viable research tool."
The NIH spent $76 million on research using fetal tissue in 2014, awarding grants to more than 50 universities, including Johns Hopkins, Maryland, Harvard University, the Massachusetts Institute of Technology, Stanford University and Yale University. In addition to Bowers, two other researchers in Maryland, both from Johns Hopkins, received federal funding.
The research is a sensitive issue for universities, and some researchers don't like to talk about the work because they fear being targets of criticism.
A University of Maryland School of Medicine spokesman made it clear that Bowers had not yet used fetal matter at that institution. The university also does not have a process set up for Bowers to buy cells derived from fetal brains once his study gets further along, said the spokesman, Chris Hardwick. If it gets to that point, he could buy it through another institution, Hardwick said.
No other researchers at the university use fetal tissue in research, Hardwick added.
The federal government prohibits the sale of fetal tissue for a profit, but use of it is legal as long as there is consent from the mother.
An ethical dilemma can arise over what it means to ask a woman this question when she is about to have an abortion, which can already be an emotional experience, said Ruth Faden, director of the Johns Hopkins Berman Institute of Bioethics.
Faden said people fall in different categories in the fetal tissue debate: They support the research, they wouldn't donate their own tissue but think others should be able to decide for themselves, or they are opposed because they object to abortion.
"One way to think about this is to recognize that at least for some people it is not possible to separate the ethics for the use of fetal tissue in research from the ethics of terminating a pregnancy," Faden said. Some people "who hold the view that abortion is never justified ... might also hold the view that anything having to do with the abortion on principle is wrong."
At Johns Hopkins' medical school, researchers using fetal tissue must follow protocols after an oversight panel approves the studies. Hopkins has a collaboration with other hospitals that perform abortions. When a researcher needs material for a study, it comes from one of the facilities, but without identifying markers that might connect it to a specific patient.
Pandey, a professor of genetic medicine, biological chemistry, oncology and pathology, uses fetal tissue to help identify biomarkers for early detection of cancers.
Fetal tissue helps researchers understand how cells make proteins, via their genetic instructions, and become different cells for specific organs or for tumors. When tumors develop, they often start making proteins (biomarkers) that are not found in healthy adults but normally found in fetal life. The trick is to find these proteins because if researchers can test for them in adults, they might signify the presence of cancer.
"What makes cells turn into organs in a fetus is made only then; it shuts off in adults," Pandey said. "The only way to understand the process is to actually study those cells. Otherwise we miss it."
Scientists don't always need aborted fetuses to get useful tissue. In diagnosing Down syndrome, for example, a blood test on the fetus of a pregnant woman offers up enough cells to show with certainty if the baby has the disease.
The debate over fetal tissue use has even entered the presidential race, with candidate Ben Carson being pressed to explain his position on the issue. Carson, a retired Hopkins neurosurgeon, co-wrote a paper in 1992 that said he had used two fetuses aborted at the ninth and 17th week of gestation in research, according to media reports.
After the release of the first Planned Parenthood video in July, Carson criticized fetal tissue research, saying that "there's nothing that can't be done without fetal tissue" — a contradiction to his position in 1992 when he said fetal tissue research should not be banned and was not immoral.
Earlier this week, Carson told The Washington Post that he thought his research was useful and fetal tissue use should not be banned.
"When we obtain tissue like that, we want to know what the origin of that tissue is developmentally," he told The Post. "Knowing that helps us determine which patients are likely to develop a problem. It's one of the reasons why at the turn of the last century, the average age of death was 47. Now, the average age of death is 80. Using the information that you have is a smart thing, not a dumb thing."
Despite the controversy, fewer than 25 percent of biomedical researchers use fetal tissue for lab studies, according a recent poll conducted by Genetic Engineering and Biotechnology News. Only 0.2 percent of total NIH funding goes to the practice.
Research looking for alternatives to fetal tissues, such as stem cells derived from adults, is also underway, but still in the early stages.