Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Birth Defects ?
    ### Response:
    A birth defect is a problem that happens while a baby is developing in the mother's body. Most birth defects happen during the first 3 months of pregnancy. One out of every 33 babies in the United States is born with a birth defect.    A birth defect may affect how the body looks, works or both.
    