The causes of low birth weight babies are quickly being uncovered. We will focus on what be believe to be the most important causes: the genetic background of the mother and the baby, the age of the mother, her nutrition level, her access to prenatal care, and whether or not she smokes. These factors are considered in order of their amount of internal or biological causes (i.e. genetics is entirely biological and unchangeable whereas smoking is entirely environmental). These primary determining factors are the focus of much attention both nationally and internationally. Each one by itself can cause low birth weight, but they almost always happen together in predictable ways.
