Final answer:
Primary ciliary dyskinesia (PCD) causes recurrent respiratory infections and immotile sperm due to dysfunctional cilia and flagella, often stemming from genetic mutations.
Step-by-step explanation:
Men with primary ciliary dyskinesia (PCD) suffer from recurrent respiratory tract infections and immotile sperm due to the dysfunction of cilia and flagella. These structures are essential for movement and for the functioning of various cells in the human body.
PCD is often caused by genetic mutations that lead to structural and functional abnormalities in the cilia and flagella. In the respiratory tract, cilia function to trap and expel pathogens and debris; when they don't function properly, individuals are more susceptible to respiratory infections.
In the male reproductive system, the flagella on sperm are responsible for propulsion, allowing the sperm to reach and fertilize an egg. Defective flagella result in the immobility of sperm and thus infertility.