Code of Life, Codes of Conduct

Students learn in "Genes and Society" that genetic dilemmas are not confined to the lab.

IT WAS STILL CLOSE TO the beginning of term, but biology professor Robert Gross wasn't holding back. "We're here to learn the science of genetics and to think about what it means to you and your family for the rest of your life," he tells the 46 students seated in the sloping lecture hall in Gilman Life Sciences Laboratory.

First up: a genetic defect called phenylketonuria (PKU). Occurring in 1 out of every 5,000-6,000 births, PKU causes severe mental retardation if left untreated.

"You can test for PKU in infants and regulate it with a rigorous diet," Gross explains. End of story? Not quite.

Although human tinkering with genes dates back to the seeds of agriculture 10,000 years ago, Gross's students stand at the brink of adulthood at a time of unprecendented expansion and manipulation of genetic possibilities. As the recently completed Human Genome Project opens biological doors, bioengineered foods fill supermarket shelves and cloning leaves the realm of science fiction, scientists and lay people alike face the farreaching implications such advances carry. "You can't pick up a newspaper without reading stories about biology and society," Gross says. So he is introducing his class to the web of medical, social, financial and ethical issues surrounding this new age of genetics.

In class Gross, 55, continues with his discussion of PKU. "Back in the 19705," he says, "a study estimated that screening all American infants for PKU would cost $3.3 million per year." He writes the number on the blackboard. "It costs $189 million per year to care for patients in mental institutions because of PKU." He writes that number down, too. The economics of screening seem clear enough. But then he asks, "Do you think legislation should be passed to require PKU screening? Should the federal government do something for the general good of the public?"

A student speaks up: "As long as it doesn't impose on the individual."

"How do you determine if it imposes?" Gross asks rhetorically.

He continues. In the 1970s about 40 states mandated PKU screening. Now all do. "It has been very successful," he says. "But now women who control their PKU through diet are having babies. And it turns out that those babies are at high risk for serious problems, including mental retardation, microcephaly and congenital heart disease. What do you do to prevent this situation? Mandatory sterilization for women with PKU?"

A student suggests counseling the mothers about the risks.

"PKU affects intelligence. Many of these women might not be capable of benefitting from counseling," Gross replies. "Considering the problems and expenses of dealing with the babies' medical conditions, would it have been better to have placed the mothers in mental institutions when they were infants? And who should make that decision the parents?"

"It's a moral issue, not an economic one," a student offers.

"What about when it affects what a family can do, like taking their normal kids on vacation?" Gross poses.

"Parents have to be ready to raise their children, no matter what," a student says.

"But after years of care, stress levels can be high. It's human nature," Gross replies.

"There was that recent case of a CEO and his wife dropping off their disabled son at a hospital because they couldn't cope with him any more," a student recalls.

Gross nods. Then he widens the issue even further. Humans have approximately 100,000 genes, and each one of us has a handful of defective genes, he explains. "In the future,we maybe able to examine 50,000-60,000 genes in one test to find out your five or six bad genes. Should we do such testing?" He lets the question penetrate. "These are complex issues," Gross continues. "By comparison, PKU is simple."

The class takes a 10-minute break before the second hour of lecture. When the students return, Gross invites everyone to express any opinion, "extreme or not."

He's not just trying to liven up the class discussion. He's making a point about the real world. "In order to make decisions that make sense, we need to know all views," he says. "I will stand up vehemently to make room for any viewpoint."

The students become more talkative as Gross takes them through the genetics behind cystic fibrosis, sickle-cell anemia and the fatal Tay-Sachs disease. He segues into genetic screening and counseling. "Should parents be able to know if their unborn child will be okay?" he asks.

"Where do you draw the line? Would you reject a fetus that doesn't have blue eyes and blond hair?" a student responds.

"What about Tay-Sachs—where there's no life expectancy? Should we screen for that but not for blue eyes and blond hair?" Gross asks.

His final example of the day concerns a couple who has two children and wants a third. The parents want genetic screening to make sure the new baby is just like them, unlike their other children. The catch: The parents are deaf. "Does that change how we think about parents' wishes?" Gross asks. "Are we making value judgments, however subconsciously? Is this any different from the PKU choice?"

Gross doesn't expect instant answers. "My point," he tells the class, "is that processes like genetic screening raise questions for all of us. Most of us would probably say it's okay not to bring a Tay-Sachs child into the world. It's not so clear about some of these other matters."

Later, in his office, Gross explains why he is so keen to teach this introductory course (this is his fifth time)."l love the interaction. I love the challenge of teaching non-scientists the science. Many students have had bad experiences with science in the past. I try to impart a sense of the wonder I feel about how things work," he says. He eases the learning process by posting lecture notes on the course Web site. "I don't want students to be so busy taking notes that they don't participate in discussions," he says.

Throughout the remainder of the term, Gross leads discussions about a wide scope of genetic issues that will impact students' lives. There's inheritance, or "how we end up being the people we are," as he puts it. There's nature versus nurture—"Neither by itself completely specifies most situations," he sums up. He sets students straight on probability. "Having the breast cancer gene, for example, doesn't mean you are going to get it—rather, that you are more likely to get it," he says. And he spends a lot of time explaining how genes work. "All 100,000 of our genes have to be regulated," he says. "Science understands some of how this happens. Mainly we understand that we don't understand."

Which is all the more reason for students to learn to distinguish between the known and the unknown. In fact, Gross, who advised novelist Michael Crichton on the scientific accuracy of his bestselling novel Jurassic Park, measures the success of his course one open mind at a time. "I want students to be able to pick up an article in The New York Times and evaluate the argument intelligently, recognize extremes and draw their own conclusions," he says. "I want them to be unafraid to go to the scientific literature. I want to remove the fear of science."

Double Helix "Genes don't determine exactly how we're going tobehave," says professor Robert Gross."That's a main point of this course."

COURSE: Genes and Society PROFESSOR: Robert Gross PLACE: Gilman 101, four hours per week. GRADE BASED ON: Two exams, one paper, class participation READING: Dealing withGenes: The Language ofHeredity by Paul Berg and Maxine Singer (University Science Books, 1992; $38). WEB SITE: www.dartmouth.edu/ ~cbbc/courses/bio4/ bio4-2000/index.html