RESUMEN
Sun is at the origin of life. It can also be responsible for death. In the past decades cutaneous melanoma killed more and more young adults. Currently, the disease still progresses in the population, but survival increases hopefully. Sun is pointed out as the main culprit. Hence, protection against harmful effects of ultraviolets is mandatory. However, preventive measures to be taken generate heated scientific argument. Sunlight exposure particularly in moderation is indeed necessary for health through vitamin D3 synthesis and psychological effects on wellbeing. Vitamin D3 provides numerous biological effects, particularly on bone calcification and also by inhibiting proliferation and migration of malignant cells including melanoma cells. Hence, we are facing the dilemma between too much and too little ultraviolet light exposure. Anyway, one cannot advocate that people lie in the sun until they burn or until they turn a rich brown complexion.