It was early April 1986, the second day on the job for the new assistant to Dr. Kook Ben Ahn, a Baltimore gynecologist. The last patient of the afternoon had just left, and the 20-year-old assistant, a patient of Ahn's in the past, asked him if he would examine a pelvic condition that had been bothering her.

Fresh from a physician's assistant course, the woman knew the routine well: She lay down on the table and placed her feet in the stirrups with a sheet draped over her knees.

But Ahn did not examine her. He raped her.

On Nov. 12, 1986, a Baltimore Circuit Court judge convicted the 47-year-old physician of forcible rape and sentenced him to a five-year suspended jail term and 1,000 hours of community service.

Under state law, that conviction could have cost Ahn his medical license. It didn't. The Maryland Commission on Medical Discipline took up the case seven months after the criminal conviction and voted to allow him to continue practicing gynecology as long as a chaperone was present during physical examinations. He is now practicing at the Rosedale Walk-In Clinic in east Baltimore.

The action by the commission in the Ahn case is not unusual. An examination by The Washington Post of all of the commission's 157 formal disciplinary actions over the past two decades shows that doctors in Maryland rarely lose their licenses, even when they are convicted in court of crimes of moral turpitude or are found by the commission to be incompetent, both violations of the state's Medical Practice Act.

The commission has disciplined doctors for violations ranging from performing unnecessary surgery to prescribing bogus treatments for cancer. Since the commission's creation in 1968, 18 doctors have lost licenses on grounds ranging from drug distribution to incompetence. Only two doctors have had their licenses revoked on grounds solely related to poor patient care. Two dozen other physicians the commission found incompetent were allowed to continue to practice, in some cases with temporary restrictions.

In the past 20 years, three quarters of the doctors who have been disciplined were, like Ahn, put on probation by the commission, enabling them to continue to practice with some temporary restrictions. Among those are doctors who have been convicted -- in some cases jailed -- for serious crimes, including sex offenses, theft, narcotics distribution and Medicaid fraud.

There is no precise way to compare Maryland's record of disciplining doctors against other states because each jurisdiction has different laws and structures governing medical improprieties and incompetence.

But what is clear is that there is little satisfaction with the way Maryland's 11,000 doctors are regulated. As a result, legislation to toughen sanctions against doctors is likely to be a priority when the Maryland General Assembly convenes for its 90-day session on Wednesday.

The Maryland system is fraught with weaknesses.

For one, the state relies on doctors not only to monitor but also to investigate one another. Compounding the problem of accountability, the physician-dominated commission conducts its business behind closed doors. There is no public record of its deliberations in any case.

Moreover, the commission is structurally weak. It has a tiny budget and no investigative staff, a large obstacle in launching and proving cases involving incompetence. Many cases drag on for years.

The commission seldom uses its full powers under the law, such as emergency suspension of licenses. And while state law allows the commission great latitude in determining penalties, there are no situations -- such as a conviction for rape or drug distribution -- in which a license is revoked automatically.

Finally, the commission's actions are rooted in a philosophy that favors rehabilitating doctors rather than punishing them.

Commission members, citing confidentiality rules, decline to talk about their actions in specific cases, making it impossible to know the intricacies of the process used in determining sanctions against doctors.

Here is a sampling of commission actions:The commission has made two disciplinary findings against Dr. Richard Buyalos, a Baltimore obstetrician/gynecologist, for poor patient care, specifically in his use of excessively radical surgery, unnecessary cesarean sections and inadequate fetal monitoring. The commission still allows him to practice, with some restrictions. As part of its effort to rehabilitate rather than punish doctors, the commission allowed Dr. Clarence Coombs, a psychiatrist who served jail time for Medicaid fraud and drug distribution, to keep his Maryland license as long as he practiced only in a supervised setting in a state mental hospital. Texas authorities, meanwhile, revoked his license there after learning of his convictions in Maryland. The commission did not act until it received two extraordinary court requests that it evaluate Dr. Clarence Beverly, despite allegations in a lawsuit that the Baltimore anesthesiologist was brain damaged and had caused the death of a young woman during surgery to remove a small cyst. A Different System

Commission members say they grow concerned when their efforts are judged by the number of licenses they suspend or revoke -- "the public clamor for a body count," as one member termed it. They say that, in general, they try to fashion disciplinary actions that protect the public from harm while salvaging the doctor's career.

"Sometimes it's to the public's benefit to allow the physician to continue to practice," said Dr. Ronald Taylor, vice chairman of the commission. Lifting a doctor's license "may hurt the public when the person can be rendering good care," he said.

Doctors on probation may also be required to undergo psychotherapy or take additional training. "If we take away his livelihood, how are they going to pay for all those things?" Taylor said.

Commission members also say that Maryland shares some of the same problems of other states in grappling with physician discipline -- a point supported by federal studies that show that physician discipline is lax nationwide.

What is different in Maryland is the system.

The commission has no autonomous investigators, unlike comparable agencies in most states. It relies primarily on the state medical society, the Medical and Chirurgical Faculty of Maryland -- the group that lobbies the Maryland General Assembly on behalf of doctors -- and on county medical societies to provide volunteer investigative help.

The ties between the commission and the medical society, commonly called Med-Chi, go even further: Med-Chi nominates a majority of the commission's 11 members.

As a result, the commission has become a creature of the medical establishment, reluctant to take strong action against its own, say its critics, among them lawyers, legislators and reform-minded doctors.

Whatever its inclination, the commission is hard pressed to accomplish much. It is a part-time board, whose $340,000 budget is enough to pay a small clerical staff, an executive director and a part-time physician consultant, but not enough to hire investigators and attorneys needed to put together airtight investigations that could stand up in court if doctors appeal commission rulings.

One consequence is that the commission has been unable to keep up with its staggering caseload -- which has increased 38-fold since 1969, its first year in operation. As complaints have mounted, there has been no overall increase in the number of disciplinary actions it takes.Process Often Takes Years

Complaints against a doctor -- some of which involve accusations of dangerous incompetence -- often take years to investigate and resolve. The commission received 862 complaints last fiscal year, for example, but held only four hearings and revoked one doctor's license.

It issued disciplinary sanctions against 11 physicians, closed 510 cases, including some left over from the previous year, and concluded the year with a backlog of 735 active cases.

"The commission moves at the speed of a glacier," said Marvin Ellin, a leading attorney in medical malpractice.

The commission reported that it took 15 to 18 months to resolve the average complaint in fiscal 1987. That delay has been reduced somewhat to about 11 months, according to commission Executive Director Margaret Anzalone.

"They've done a miserable job," said Roy Mason, a defense lawyer who represents doctors in disciplinary proceedings and malpractice lawsuits.

"They're not iron-fisted enough," said Dr. William Finney, a well-known neurosurgeon who is involved in the medical community's legislative efforts and professional peer review. "Good physicians want bad physicians out."

Del. William Horne, an influential Talbot County Democrat who is chairman of the House Judiciary Committee, said he believes inadequate physician discipline has reached a crisis stage in Maryland. His committee, under pressure from doctors and insurance companies seeking relief from spiraling malpractice insurance costs, has passed several bills making it more difficult for malpractice victims to recover damages from doctors.

But Horne and others in state government, including Gov. William Donald Schaefer and Attorney General J. Joseph Curran Jr., are convinced that the medical profession needs to do much more to weed out bad doctors who drive up the cost of insurance for physicians statewide. In November, Horne met with commissioners to tell them he thinks discipline needs to be stronger.

"They don't want to talk about that," Horne said. "{Some} of them believe there is no connection between incompetence and malpractice, which seems ludicrous on its face."

Commissioners are acutely aware of the concern in Annapolis, and this winter are considering whether to take tougher sanctions against errant doctors, according to Dr. Hilary O'Herlihy, chairman of the commission. He said members are also looking for ways to speed up the investigation process.

Legislative impatience with bad doctors also has begun to worry Angelo Troisi, executive director of Med-Chi.

Despite his organization's close ties to the commission, Troisi said he thinks the commission has serious failings in both process and philosophy.

Troisi has vigorously defended the disciplinary system in Maryland. But, he said, Med-Chi has begun reevaluating the commission's effectiveness and encouraging commission members to do the same in light of concern in the state capital.

According to Troisi, doctors around the state are upset about the commission's action in the Ahn case and other commission actions in which incompetent doctors or those convicted of criminal offenses have been allowed to continue to practice.

"Physicians in Maryland are not going to tolerate this kind of response," Troisi said. "We don't want to worry the public, but I'd be lying if I didn't tell you we're getting less than the desired results."

Part of Med-Chi's recent interest in improving medical discipline stems from a hearing last fall during which Horne told commissioners that, particularly given the passage of legislation to reduce malpractice insurance costs, doctors would need to do much more to police themselves.

"We'd like to see some more quid pro quo," Horne said. "Don't ask us to do anything more to my constituents and your patients until you do something to discipline your doctors."

In response to such concerns, members of the commission often state their philosophy that the commission's proper role is to retrain or rehabilitate doctors when possible, not to punish them.

"Our first duty is to protect the public; our second duty is to be humane," said Taylor, the commission's vice chairman. A criminal conviction such as Ahn's "may be prima facie evidence" that a physician should be disciplined, he said, "but that doesn't mean we have to strip them of their right to breathe or whatever."Rights vs. Protection

The Ahn case is just one recent example of how the commission's goals of protecting a doctor's rights and protecting the public can come into conflict.

"It's shocking to see a doctor convicted of a very serious felony continue to practice," said state Sen. Gerald Winegrad (D-Anne Arundel), who has urged the governor to increase the commission's staff.

Dr. Israel H. Weiner, a leading physician and former Med-Chi president who is familiar with the Ahn case, said "it's crazy" that the commission did not punish Ahn more severely. "I think it's inconceivable that they would let a guy like that continue to practice medicine."

Commissioners declined to discuss the Ahn case, as did Ahn, who denied the rape charges both before the commission and in the criminal trial. His lawyer also declined to comment.

But prosecutor Olga Bruning said that several months after the conviction she called the commission to find out why it had not taken away Ahn's medical license and to urge it to do so. "They said they didn't consider it an emergency," she said. "I said, 'You don't consider a doctor raping patients on the table an emergency?' "

When she learned the commission voted to place Ahn on probation instead of removing his license, Bruning said, she was "just horrified."

So was Alice Ike, an assistant attorney general who presented the case against Ahn to the commission. "As a woman, I was outraged," she said. But, she added, "I guess I'm never surprised at what I see the commission do."

Under the terms of the five-year probation set by the commission, Ahn cannot practice alone and he must have a chaperone in the room when performing examinations, protocol recommended by the state Obstetrical and Gynecological Society.

Ahn lost his medical privileges at Church Home and Hospital, but currently is treating clinic patients at Rosedale. Clinic officials there did not respond to telephone calls or to written inquiries about his employment.

Baltimore Circuit Judge Elsbeth Bothe said in an interview that she decided to suspend Ahn's jail sentence because a number of his physician colleagues testified to his good character.

"When I sentenced him I said I thought the loss of his livelihood would be more serious than a jail sentence," Bothe said. "I did not really expect that he would be able to practice again."

Next: The price of incompetence.