Hi, Sometimes even smaller testes do not cause any problem of health. However if they are causing some problem like infertility, erectile dysfunction, decreased sexual drive or thin body muscle mass, then the cause of small testes must be looked for and treated accordingly. The causes as such varicocele, torsion of testes, infection of testes undescended testes, should be looked for and managed accordingly. Hypogonadism primary or secondary should be also treated if present. A study of level of hormones like luteinizing hormone and testosterone may be required and treatment may be needed for this. Particularly low sperm count, erectile dysfunction and infertility due to low testosterone levels may need testosterone replacement therapy under guidance of your doctor. Infertility in addition may require treatment with drugs like clomiphene citrate etc. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Satnarain Bansal, General & Family Physician