Vivek Murthy, 36, a Boston physician, software entrepreneur and Obama political ally, is a "relatively inexperienced and untested physician" who doesn't have the "right" yet to be viewed as a potential surgeon general, Richard Carmona, surgeon general in the George W. Bush administration, said in a letter to Obama.
A candidate without considerable public health experience risks being put at "a distinctive disadvantage in credibility, knowledge and depth and breadth of experience when attempting to address complex public health issues," Carmona said in the letter, cited by Politico.
Kenneth Moritsugu, a deputy surgeon general in the Clinton administration and an acting surgeon general in the George W. Bush administration, told Politico he wasn't "for or against" Murthy's nomination.
But he echoed Carmona's comments about the importance of experience in the public health field.
"There is concern regarding an individual's background and experience," Moritsugu told Politico.
"In addition, the surgeon general, while politically appointed, needs to become science-based upon acceptance and confirmation and swearing-in," he said. "Science-based is extremely important in being a successful spokesperson to and for the American people, and individuals who are younger in their career may not possess those capabilities."
Murthy's confirmation hearing before the Senate Health, Education, Labor and Pensions Committee was to start at 10:30 a.m.
Murthy, who ran Doctors for America, a physicians' association that backed the Affordable Care Act, is an attending physician at Boston's Brigham and Women's Hospital in Boston. He also teaches at Harvard Medical School.
He earned his medical degree and a business degree at Yale University before starting a rural health program in India.
Obama appointed Murthy in 2011 to serve on the Presidential Advisory Council on Prevention, Health Promotion and Integrative and Public Health within the Department of Health and Human Services.
Murthy was born in England to parents from India. He grew up in Miami, where his father practiced medicine.
Friends and colleagues told the Boston Globe he's congenial, smart, driven and more than qualified for the position.
If confirmed, Murthy would be one of the youngest surgeons general in history.
He is widely expected to be more vocal than recent surgeons general, including immediate predecessor Regina Benjamin.
Benjamin resigned July 17, 2013. Rear Adm. Boris Lushniak has been acting surgeon general since that date.
The surgeon general is the leading spokesperson on matters of public health in the federal government.
Notable deaths of 2014 [PHOTOS]