Answer:
Step-by-step explanation:
As people age, they tend to slide towards impotency. However, this can occur early in life due to different things like alcohol, drugs, stress, etc.
So if you are not old, I would contact your doctor to see if you have any genetic, pathogenic, or some kind of condition which causes you to be impotent.
If you are old, it might be normal, nonetheless, calling your doctor is safe bet.
There are also drugs that can induce the action you desire but consult with your primary care doctor to see if it interferes with your normal developement or interefers with any other drugs you might be on.