Former White House physician Kevin O’Connor, DO, invoked the Fifth Amendment during a House Oversight Committee hearing as GOP members probed allegations of cover-ups related to former President Joe Biden’s cognitive decline.
The closed-door session, led by Rep. James Comer of Kentucky, continued an ongoing investigation into whether Biden’s former aides concealed signs of mental or physical deterioration while in office and whether any executive decisions were made without the president’s full knowledge. O’Connor, who served as Biden’s White House physician from 2021 to 2025, refused to answer questions about Biden’s mental acuity, citing constitutional protections.
Critics, including former White House physician Dr. Marc Siegel, argued that O’Connor’s refusal to speak highlights the importance of medical transparency in assessing the health of a sitting or former president. Siegel, a Fox News medical analyst, emphasized that both DOs and MDs have the same educational qualifications and clinical capabilities, including diagnosing and treating cognitive decline or prostate cancer.
“He’s a DO and a family practitioner,” Siegel said. “With that training, he should know how to screen for prostate cancer.” Siegel added that while DOs focus on a holistic, mind-body approach, their training does not limit their ability to diagnose or treat neurological conditions. He expressed concern that the lack of a clear response from O’Connor may have undermined the credibility of the medical assessment of Biden’s cognitive health.
The hearing also sparked a broader discussion about the professional equivalency between DOs and MDs. According to the Cleveland Clinic, both types of physicians undergo similar schooling, can prescribe medication, and have identical practice rights. The key distinction is that DOs receive additional training in osteopathic manipulative medicine (OMM), emphasizing whole-person wellness and prevention. However, both types of doctors can use modern medical treatments, including surgery and medication.
DO training originated in 1892 when Dr. Andrew Taylor Still, MD, developed a new philosophy of medicine after the Civil War. He believed traditional methods were ineffective in treating illness, particularly after losing three of his children to spinal meningitis. This led to the creation of osteopathic medicine, which focuses on mind-body connections and holistic treatment. Today, there are 38 osteopathic medical schools in the U.S. as of 2023, compared to 154 allopathic medical schools.
O’Connor was appointed to the role in March 2021 by Biden. He was replaced in March 2025 by Dr. Sean Barbabella, DO, a Navy physician with a decorated career in military medicine. Prior to taking the role, Barbabella had served as the chief of the Naval Health Clinic Cherry Point in North Carolina. Before him, Dr. Sean Conley, DO, served as Biden’s physician-in-chief during his first term, from 2017 to 2021.
Biden allies have been pushing back against the GOP investigation, arguing that the allegations are politically motivated. However, House GOP members, including Rep. Ronny Jackson, a former White House physician himself, continue to press for answers. They are seeking more information on whether any executive actions were made using the autopen without Biden’s knowledge and whether his aides concealed signs of his decline.
The discussion has also led to a renewed interest in the qualifications and roles of osteopathic physicians, particularly in high-profile political or public health contexts. As the investigation continues, the focus remains on the transparency of medical assessments, the responsibilities of top White House physicians, and the broader implications for public trust in both medicine and politics.