Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Y chromosome infertility ?
    ### Response:
    Y chromosome infertility is a condition that affects the production of sperm, making it difficult or impossible for affected men to father children. An affected man's body may produce no sperm cells (azoospermia), a smaller than usual number of sperm cells (oligospermia), or sperm cells that are abnormally shaped or that do not move properly.
    