No problem or patient is “too small”Âť in Mark Cohenâ€™s eyes. Before joining the group, Dr. Cohen was a neonatology fellow in the Holden Perinatal Care Unit at the University of Michigan and spent one year caring for critically ill, premature and newborn babies in that special care facility. Dr. Cohen likes to sail, travel, exercise, read and play chess. He lives in Acton with his wife, who is also a physician and is the Clinical Chief of Infectious Diseases at The University of Massachusetts Medical School. Their children both graduated from Acton Boxborough Regional High School, as well as from Wesleyan University. Their son is a lawyer and works for Health Law Advocates in Boston. Their daughter is an Internist at Acton Medical.