The baby was born with a cleft palate, clenched hands and a number of internal defects, including a heart problem that could have killed him in a few months. But that's not what he died of. An autopsy report listed the cause of death as cranial cerebral injury, skull fracture and blunt trauma. The baby's father, 35- year-old John McKay, described by a neighbor as a man with "a heart of gold," faces a preliminary hearing today on charges of pounding the child to death.

According to United Press International, several nurses at Ingalls Memorial Hospital in Harvey, Ill., said they saw McKay, who 30 minutes earlier had witnessed the baby's birth, take the infant out of the incubator. McKay, it is alleged, then repeatedly bashed the baby's head against the floor and then flung him into a corner of the room.

It's such an awful, gruesome thing that it may be gratuitous to try to draw any conclusion, except, possibly, temporary insanity. And yet there are other conclusions--questions, anyway--that won't go away. For instance:

In what way is the thing McKay is charged with different from what doctors in other cases have freely (if agonizingly) admitted? I think of "Infant Doe," the deformed Indiana baby whom doctors allowed to starve to death rather than repair his incomplete esophagus. (The baby also had Down's syndrome.) Does it matter, except, perhaps, esthetically, whether death comes as a result of withheld medical care, starvation, injection or bashing? Does it matter whether the killing is performed by a doctor as agent of the parents or by the parents directly? Does it matter whether the act involves malice against the infant or only sympathy for the parents? Whether the killer is nasty or kind? McKay, a veterinarian with a "heart of gold," apparently is kind enough. "I had to put my dog to sleep last week," a neighbor said, "but he worked for two days trying to save her before he would do it. He cared for animals and he cared about people."

And then there is this question: what is the crucial difference between killing a defective newborn infant whose deformities were previously unknown and killing an unborn baby as soon as serious defects are discovered? Is there a moral distinction between bashing the head of a half-hour-old baby and using a saline injection to kill the same baby a half-hour before birth? (As I understand the Supreme Court ruling, the prohibition against third-trimester abortion had more to do with the mother's safety than with protecting the child.)

Some who describe themselves as being "pro-choice" insist there is a crucial difference between killing a baby and interrupting a pregnancy, no matter how far advanced. Is this a distinction without a moral difference?

I don't pretend that the answers are, in all cases, easy. I do say that the allegations against McKay give the questions new urgency. The doctor in the McKay case permitted himself one interesting conclusion: "I think this is a fine example," he said, "of the faults of having a father present at childbirth." I won't try to guess what he would have said if it had been the mother who was charged in the case.