What causes groin hernias?

No specific cause. Groin or inguinal hernias are quite common in men, and may be somewhat hereditary. It is a weakness in the fibers that may be weak since birth. Can sometimes be associated with heavier lifting or repeated straining.
Unknown. The exact cause for any individual is unknown, but several factors are know to cause hernias such as a genetic collagen disorder, lifting heavy objects, coughing, or any activity that involves sudden and repeated increases in pressure inside the abdominal cavity.