Despite nearly two weeks of deliberations, a jury remained undecided Friday on the fate of abortion doctor Kermit Gosnell, who faces numerous murder charges for allegedly snipping the spinal cords of babies born at his clinic in West Philadelphia.

Jurors have spent hours in recent days re-hearing testimony of key witnesses, suggesting that they continue to wrestle with a peculiar legal quandary at the heart of the case: In order to find Gosnell guilty of murder, they must first agree that the babies were ever actually alive outside the mother’s womb.

That has remained a central dispute throughout the high-profile trial, which began in March.

Gosnell’s attorney, Jack McMahon, has argued that no live births took place at the clinic because Gosnell terminated the pregnancies in utero using a drug called digoxin. A medical examiner could not say conclusively whether any of the infants had been alive after delivery, in part because their remains had long been frozen in a clinic freezer.

Jurors have been left to rely primarily on the eyewitness accounts of uneducated, untrained former employees who have testified that women often gave birth in the clinic after being pumped full of drugs to induce labor. They also have described seeing infants move or make noises after birth, just before Gosnell severed their spinal cords with scissors. Some of those same employees themselves performed abortions and already have pleaded guilty to crimes, including third-degree murder, while agreeing to testify against their former boss.

Gosnell, 72, faces first-degree murder charges in connection with four babies, known in court as A, C, D and E. He also faces allegations of third-degree murder in the death of a 41-year-old Virginia woman, Karnamaya Mongar, who died in 2009 after receiving an overdose of drugs during an abortion at his clinic.

In addition, he faces 227 counts of failing to abide by Pennsylvania’s 24-hour waiting period before performing an abortion, two dozen counts of performing abortions beyond the state’s 24-week legal limit and various other charges, including conspiracy and running a corrupt organization.

Prosecutors, who have portrayed the Women’s Medical Society on Lancaster Avenue as a “house of horrors,” have said they intend to seek the death penalty if Gosnell is convicted on any of the first-degree murder charges.

Deliberations are scheduled to continue Monday.