The process during which a fertilized human egg develops from embryo to fetus to newborn is an exquisitely timed and delicately balanced one that is dependent upon the dictates of a multitude of genes. These genes carry a wealth of information including the heritable traits that elicit those post-birth coos from relatives and friends. Characteristics or conditions that are heritable are intrinsic to the genetic makeup of an individual and are capable of being passed from one generation to the next. Conditions or characteristics that are congenital, on the other hand, are usually not part of the organism’s normal genetic makeup. Congenital, derived from Latin com-, meaning “together,” and genitus, meaning “born,” describes conditions or traits that are acquired either at birth or during the nine months of development in the uterus. Most often, congenital indicates that some factor, such as a drug, a chemical, an infection, or an injury, has upset the careful timing and balance of the developmental process in a way that adversely affects the fetus. Thus, a baby can have a heritable disease such as hemophilia, which can be passed on to future generations, or a congenital condition such as spina bifida, which cannot be passed on.
