San Francisco, CA (LifeNews.com) -- The fallout from a study published in the prestigious Journal of the American Medical Association by two abortion advocates claiming unborn children don't feel pain from abortions until late in pregnancy continues.

Now, JAMA's editor says she was "unaware" that the authors of the report include an abortion practitioner and a former staffer for a leading abortion advocacy group.

The lead author of the study is Susan J. Lee, a University of California at San Francisco medical student who once worked for NARAL, an abortion advocacy group that recently came under fire for falsely accusing Supreme Court nominee John Roberts of backing abortion-related violence.

Meanwhile, another author, UCSF obstetrician-gynecologist Eleanor Drey, is the medical director of the abortion center at San Francisco General Hospital.

JAMA editor-in-chief Catherine DeAngelis told Knight Ridder News she was unaware that the two authors are intimately involved in the abortion movement. She acknowledged that revelation could hurt the credibility of the publication.

"This is the first I've heard about it," she told the Philadelphia Inquirer newspaper. "We ask them to reveal any conflict of interest. I would have published" the disclosure of the abortion ties if it had been made.

Drey, the abortion practitioner, defends her participation in the study.

"We thought it was critical to include an expert in abortion among the authors," she told Knight Ridder. "I think my presence ... should not serve to politicize a scholarly report."

Dr. Kanwaljeet Anand of the University of Arkansas Medical Center says the report is biased. He said he and other specialists in development of unborn children have shown that babies feel pain before birth as early as 20 weeks into the pregnancy.

Anand said other medical studies conclude that unborn babies are "very likely" to be "extremely sensitive to pain during the gestation of 20 to 30 weeks."

"This is based on multiple lines of evidence," Dr. Anand said. "Not just the lack of descending inhibitory fibers, but also the number of receptors in the skin, the level of expression of various chemicals, neurotransmitters, receptors, and things like that."

Anand explained that later-term abortion procedures, such as a partial-birth abortion "would be likely to cause severe pain."

Anand says the report will upset other specialists who know more about fetal development than the reports' authors.

An April 2004 Zogby poll shows that 77% of Americans back "laws requiring that women who are 20 weeks or more along in their pregnancy be given information about fetal pain before having an abortion."

Only 16 percent disagreed with such a proposal, according to the poll, commissioned by the National Right to Life Committee.