Nationwide, nearly a half million babies are born prematurely each year, according to the National Center for Health Statistics. He now plans to study what happens to extremely low-birth weight children, who are more prone to health problems, as they age. The influence of gender and race on babies' survival rates was more noticeable the smaller the infants were, the research shows. But female preemies' lungs tend to be more developed at birth, which could be part of the explanation, Morse said. Retrieved February 17, from www. Materials provided by University of Florida. It's the first scientific evidence of a phenomenon doctors have observed for years, said Steven B.