Boston Children's Hospital is a 404-bed comprehensive center for pediatric health care. As one of the largest pediatric medical centers in the United States, Children's offers a complete range of health care services for children from birth through 21 years of age. Boston Children's Hospital is home to the world's largest research enterprise based at a pediatric hospital. More than 1,100 scientists, including nine members of the National Academy of Sciences, 11 on-staff members of the Institute of Medicine and 9 members of the Howard Hughes Medical Institute. The hospital is also the primary pediatric teaching affiliate of Harvard Medical School.