When it comes to the issue of small testicles, the first thing I want to talk to you about is what small testicles are. Medically speaking, Asian testicles larger than 12ml are considered normal size, and when you check yourself, your testicles will feel like quail eggs. The small testicles I am going to talk to you about today are not all testicles that are smaller than normal, but those that feel like a green bean (actually less than 5ml). There are many different kinds of patients with small testicles, and most of them are currently able to find the cause. First of all, I will divide the small testicles into two categories according to the conditions that my friends can judge by themselves. One category of patients has small testicles, but pubic hair can be seen and the penis has developed; the other category of patients has small testicles and also a toddler type penis with no pubic hair at all. Let’s start with the first category, that is, small testicles, but pubic hair is visible and the penis has developed. Most people in this category are able to have a normal sex life. If you go to the hospital to check your semen, it is common to see that there is no sperm. Because of the small size of the testicles, the testicles do not have the appropriate sperm production capacity. If you check your hormone levels, you will find that most people have significantly higher follicle stimulating hormone (FSH) and luteinizing hormone (LH), and lower or normal testosterone (T). In the past, it was believed that the smaller the testicle, the higher the FSH value and the less sperm in the testicle. For patients with testicles less than 6 ml or with twice the FSH value, many doctors still believe that there is no value in doing testicular biopsy and treatment. But in fact, with the advent of microscopic sperm retrieval technology, there is now a radical change in understanding from the past. For these patients, it is recommended to check the chromosomes, many of them are 47,xxy (normal human chromosomes are 46,xy). In the second category, the testicles are small and the penis is not developed, it is a toddler type and there is no pubic hair at all. In these cases, it is difficult to have sex before treatment because the penis has not yet developed. For many of these patients, they may never have ejaculated, and some of those who do ejaculate have low semen volume and no sperm. At this point, our hormone tests usually show that FSH, LH and T are all very low, close to none. These are the hormones that promote the development and growth of our testicles and the production of sperm. This condition is known as IHH (Idiopathic Hypogonadotropic Hypogonadism) and is also known as Kallmann’s syndrome if it is accompanied by abnormalities in the sense of smell. The main treatment for this type of patients is to supplement the corresponding FSH and LH with HCG and HMG injections, which are commonly used clinically, and the recommended treatment period is about two years. Even in patients in their 30s, they can still grow pubic hair and enlarge their penis to adult size. More than 70% of patients are able to produce sperm and have their own children during the treatment. From the above description, it is easy to see that we now have good treatments for patients with small testicles that were completely untreatable in the past. Of course, there are still some patients who will still have no sperm, and then sperm from sperm banks will be needed to assist.