The decision follows Sunday's broadcast of the 60 Minutes program in which two doctors said they believed 8-month-old Matthew Eappen was strangled, not shaken and slammed by Woodward as prosecutors charged.
The attorneys said they don't know if the new theory is reliable, but they were glad the doctors agreed Matthew did not die from shaken baby syndrome, as prosecutors claimed.
The report has stirred another wave of controversy over the case, with a group of more than 70 physicians criticizing the CBS report as "preposterous," and the revelation that one of the doctors had been paid by defense lawyers.
Defense lawyer Harvey Silverglate said Thursday that the doctors critical of the report were mostly pediatricians and not "hard scientists."
He said the defense team called the news conference Thursday to respond to criticism and announce their decision to initiate a scientific investigation to find how Matthew died.
He said they would have their own experts review the strangulation findings and then approach prosecutors to see if they could jointly launch an independent investigation.
The result could lead to a motion for a new trial, but lawyers said that decision would depend on the findings and would ultimately have to be made by Woodward, who is attending law school in England.
"Miss Woodward has always taken the course that would vindicate her and prove her innocent," said defense lawyer Barry Scheck, who answered questions in his New York office via speakerphone.
Woodward was convicted in October 1997 of second-degree murder in Matthew's death. The trial judge reduced her sentence to involuntary manslaughter and released her from prison. She returned home to England in June, after the judge's sentence was upheld on appeal.
In January, she settled a civil wrongful death case with the baby's parents, Drs. Sunil and Deborah Eappen.
On 60 Minutes, Dr. Floyd Gilles, a neuropathologist, and Dr. Marvin Nelson, a radiologist, both affiliated with Children's Hospital in Los Angeles, offered the theory that Matthew had been strangled up to 48 hours before his hospitalization on Feb. 4, 1997.
The defense lawyers said they had not yet spoken at length with Gilles or Nelson.
They admitted, however, that Nelson had been paid $700 before the trial by the defense team. He was never called as a witness.
"His consultation was minimal," Scheck said. "It is, in fact, Dr. Gilles who is the main proponent of the strangulation theory."
In a letter sent to CBS Tuesday, the group of pediatricians and forensic experts said the network and the two doctors interviewed by the program owe the Eappens an apology.
Many of the physicians who signed the letter put their names on another missive in Novembe 1997 that attacked Woodward's defense theory. During her murder trial, Woodward's lawyers argued that the baby died from an old injury that suffered a "re-bleed" prior to his hospitalization.
The group of letter-writing physicians, led by Dr. Carole Jenny of Brown University's School of Medicine in Providence, R.I., said the strangulation theory is not supported by medical literature.
"I was pretty mystified by how in the world people can come to a conclusion that totally overlooks the skull fracture, the subdural hemorrhages and all of the other things that this child had," Jenny said Wednesday. "There's no doubt he had his skull busted open."
Moreover, they say, the theory is not supported by a paper co-written by Gilles himself in 1987.
"Our doctors have seen the evidence firsthand. These doctors who wrote the letter haven't," said Kevin Tedesco, a spokesman for 60 Minutes.
Steve Rutledge, a spokesman for Children's Hospital in Los Angeles, said: "Our doctors stand behind the results of more than six months of examining the scientific evidence in the Matthew Eappen case, and they feel it's fine for people to have differing opinions as long as those are informed opinions."
District Attorney Martha Coakley, who prosecuted the case, could not immediately be reached for comment.
When asked if they were concerned what effect rehashing the case would have on the Eappens, Silverglate replied: "We're worried about what this is doing to everybody. I can assure you Louise Woodward is not thrilled that this has come up."
Written by Robin Estrin