The factors that lead to impotency in men?

Many!: First, it is important to find out if there is a physical reason for impotence. This requires a history & physical examination by your doc, with appropriate testing. If a physical cause is found, like a hormonal imbalance, then treatment helps. You may be referred to a urologist. If there's no apparent physical cause, which is not infrequently the case, then psychological issues are possible.