The testes are a very important reproductive organ in the human body. Inside the testes are mainly testicular tissues, which include spermatogonia, mesenchymal cells, basal cells and so on. The primary function of the testes is to produce sperm, which can then be transported to the epididymis for maturation. Sperm are an important component in the formation of a fertilized egg, and only sperm can unite with an egg and then form a fertilized egg. The fertilized egg will be laid in the uterus to form an embryo, which will give birth to the next generation, so the testicles are a very important reproductive organ. In addition, you can go for a scrotal ultrasound to determine the size and density of the testicles.