Vitiligo Definition and Overview. Vitiligo is an autoimmune skin disease in which there is a progressive destruction of the skinâs pigment-producing cells (melanocytes), resulting in areas of otherwise normal white skin devoid of melanin pigment. It is not unusual for hairs growing in areas of vitiligo to lose their normal color.
Sperm Cycle. Old sperm cells die off and new cells are created at a rate of about one percent each day. This means the entire sperm cycle requires approximately 100 days. The final 75 days represent a period of maturation for the sperm cell. This final step of sperm maturation, called spermiogenesis, puts the fuel into the tank and completes the development of the sperm cell (spermatozoon).
But do men actually run out of sperm? Well, the simple answer to this question is âNoâ. Men never run out of sperm and their testicles keep on producing sperm cells until the day they die. This is why you may have heard stories of even 90 year olds fathering a child. This is very true. While women stop being fertile when they reach menopause around the age of 50-55 years, men are always fertile.