Monorchidism: Single Testis – Causes, Risks, and Care

Monorchidism (one testis) affects ~1% of males. Not "weird" – a recognized anatomical variant.

Causes

• Congenital – failure of testicular descent/genesis (genetic, hormonal).
• Acquired – orchiectomy for torsion, trauma, tumor, undescended testis.

Health Implications

• Fertility – usually preserved if remaining testis normal; semen analysis confirms.
• Hormones – single testis typically produces adequate testosterone.
• Cancer risk – contralateral testis has slightly elevated germ cell tumor risk; self-exams, annual US.
• Psychosocial – body image; counseling if needed.

Management

• Urology evaluation – confirm anatomy, rule out intra-abdominal testis (cancer risk).
• Prosthesis option for cosmesis.
• Monitor testosterone if symptomatic.