Conjoined twins born to an Orthodox Jewish family in Lakewood, N.J., 35 years ago created a wrenching moral dilemma for their parents and doctors, not to mention the rabbis the family consulted. Joined at the chest and sharing a heart, the babies were airlifted to Philadelphia and were soon failing. Only one could survive; the other would have to be sacrificed.

Was it wrong to kill one child for the sake of the other? Should both be allowed to live as long as possible, sharing their strange six-chambered heart, even though that would likely mean their imminent death?

The parents' struggle with the decision gripped observers in an era before living wills and medical advances made such choices more common. The year was 1977, a decade after the first successful human heart transplant, but seven years before the feat would be accomplished in a child.

Among those pushing the boundaries of medicine was C. Everett Koop, then chief of surgery at the Children's Hospital of Philadelphia, who would ultimately perform a risky operation on the twins. Now 95 and a former U.S. surgeon general, Koop recently traveled to Philadelphia from his home in New Hampshire to attend a reading of a play inspired by the twins' story.

The play, Choice, was written by Donald Drake, who covered the story for The Inquirer. Drake has transformed the drama into a work of fiction, introducing conflicts that go beyond the facts.

In the actual case, rabbis concluded that the surgery could go forward only if it was clear which baby had the greatest chance of living and which was dependent on the other for survival - a measure of God's will. Tests showed that the heart was mostly in "Baby B" and barely supporting "Baby A."

The case has remained very private. The parents' names were never made public, nor was the death of the surviving baby after just six days.

In the play, there is less clarity about the choice. The surgeon says he will have to choose during the operation, placing the momentous decision in his hands, not God's. Theology clashes with medicine, pitting a devout husband against a pragmatic and desperate new mother.

Koop, in the front row of the performance space at the Painted Bride Art Center in Old City, was transfixed. Though he wore a hearing aid and sat in a wheelchair, he appeared vigorous, with a full head of hair and his trademark Amish-style beard. At his side was Cora Hogue Koop, whom he married in 2010 after the death of his wife of 60 years, Elizabeth.

If anyone embodies the entrenched American conflict between religious values and modern medicine, it is Koop. An evangelical Christian opposed to abortion, Koop surprised conservatives who pushed for his appointment as surgeon general under Ronald Reagan. Once in office, he launched aggressive public-health campaigns, including one against smoking and another in favor of sex education and condom use to counter the spread of AIDS.

In the conjoined-twins case, Koop himself had consulted rabbis as he wrestled with the issues it raised. Among them was a rabbi whose son he had operated on. After the recent performance, Koop told the audience of a scene that never made the news.

"When I tied off one carotid artery and killed a child," Koop said, "I'd given no thought about what would happen to the body. I had one dead baby and one live baby; I separated them. One of the nurses took the child who was now dead and carried it to the door of the operating room. The door opened and there stood the rabbi.

"The fact that he was there," Koop added solemnly, "seemed almost like God's blessing on what I had just done."

Dorothy Brown is a former medical and science editor for The Inquirer. She blogs at http://unretiring.blogspot.com.