Long after Baby Fae has become a tough answer to a Trivial Pursuit question, the issues raised by the historic experiment which replaced her defective heart with a baboon's will affect all of us who use the American medical system.

Like Baby Fae, any individual may unexpectedly and suddenly find himself the subject of experimentation -- sometimes without knowing it. When physicians introduce new drugs or physical devices -- such as an artificial heart valve -- they are under federal regulation. But they are free to do new operations or to use old drugs for new purposes without labeling it research. Such experimentation is frequently veiled under the banner of "new therapy."

Under such circumstances, any reasonable patient would want to be fully informed of his options. Anything less limits his right to how he shall live and die. But we don't know whether these rights were protected in the Baby Fae experiment because of the secrecy surrounding the case.

Did the baby's parents know about the alternative operation available in Philadelphia -- which has about a 40 percent success rate -- as opposed to total uncertainty as to what might happen with a baboon heart transplant? Did they understand the greater likelihood of success with a human transplant, despite the scarcity of donor hearts? Do they understand that if the baby's immature immune system does not reject the baboon heart, as hoped, it may also fail to do its normal job?

Just as important, were the parents given this information as soon as the experiment was contemplated, when there was time to take another option? Were they in any way coerced into accepting the experiment by offers of free medical care?

How medical researchers inform any individual patient reflects, in general, the way they will inform the majority of us who someday will need similar protection.

The Baby Fae case, moreover, raises even broader questions. Specifically, medical adventurism.

The Barney Clark case proved how a single dramatic event can draw patients from around the world. We may be entering an era of medical centers vying with one another in producing unproven and possibly unsound medical "spectaculars" in order to maintain or enhance their positions. Adventurism or personal gain has driven many medical experimenters.

Even if a patient agrees to an experiment, is it ethical to perform human experiments -- which distraught relatives cannot resist -- with a low probability of success?

Perhaps most important of all, a few medical researchers at Loma Linda are in the process of establishing a policy that could affect us all. Once custom is set -- in medical practices as well as other forms of social behavior -- deviation brings risk of punishment.

If, some day in the future, the parents of a baby with a fatal heart defect refuse a baboon transplant, will the government seek to prosecute them for murder? The recent attempts to enforce pursuit of all possible means of saving handicapped babies -- as in the "Baby Doe" case -- should alert us to the possibility.