TGF-β superfamily members have been implicated in various stages of lung development in utero and postnatally and in the pathogenesis of many of the features of both “new” and “old” BPD including parenchymal fibrogenesis, remodeling of the pulmonary vasculature and ASM remodeling. This evidence concerns the gene TGFB1 and bronchopulmonary dysplasia.