**Core Concept**: Varicocele is an abnormal dilation of the pampiniform plexus veins in the scrotum, typically on the left side. It is a common cause of male infertility and often presents with testicular pain, swelling, and decreased fertility. The correct options should address the pathophysiology of varicocele.

**Why the Correct Answer is Right**: Option D, "varicocele does not affect fertility," is incorrect because varicocele leads to increased venous reflux, decreased sperm concentration, and abnormal sperm morphology. These changes result in decreased fertility.

**Why Each Wrong Option is Incorrect**:

A. "Varicocele is a congenital abnormality" is incorrect because it is not a congenital abnormality but develops due to valvular incompetence in the pampiniform plexus veins.

B. "Varicocele is a result of long-standing varicoceles" is incorrect because varicocele can develop at any age and does not require long-standing varicoceles to cause fertility issues.

C. "Varicocele resolves on standing" is incorrect because varicocele persists regardless of the position, although symptoms may worsen in the upright position due to increased venous pressure.

**Clinical Pearl**: A correct understanding of varicocele pathophysiology is essential for diagnosing and managing patients with infertility issues. By focusing on these details, physicians can provide appropriate treatment options for patients affected by varicocele, improving their fertility potential.