Medical Genetics about 3% of babies are born with birth defects each year, according to the U.S. Centers for Disease control and prevention -and of the malformations that do occur the most common are also among the most treatableMedical Genetics About 3% of babies are born with birth defects each year, according to the U.S. Centers for Disease Control and Prevention - and of the malformations that do occur, the most common are also among the most treatable