Since the 1960s, my scientific activity has focused on the diagnosis and treatment of metabolic diseases, rare pathologies which, in some cases, cause irreversible brain damage. “Irreversible” is the word that should trigger all preventive efforts and ensure widespread screening. Its prevention implies early diagnosis and treatment. The fundamental objective was to detect avoidable hereditary diseases in newborns, which generally lead to irreversible mental retardation. In a short time, accompanied by the “luck of the bold”, we detected a first case of phenylketonuria and the pilot plan was set up, which led to its successive implementation throughout Spain and participation in specialised international meetings was initiated, as well as biochemical and genetic research, to contribute to scientific knowledge of such an important aspect of preventive medicine. As with any social, environmental or clinical phenomenon, it is necessary to apply treatment in time before the alteration that is to be avoided occurs, particularly when irreversible situations are involved. On several occasions I have referred to the need to act in a timely manner in order to stop the process at stages prior to the point of no return (ethics of time). Every day I feel more and more strongly, and I try to express it in this way, that the search for, dissemination and application of knowledge is the most beautiful task offered to man’s terrible perplexity, astonishment, doubt and fear. I remember that a few months after finishing my degree in Pharmacy, when I was starting to work in Prof. Santos Ruiz’s laboratory, I visited an institution for the mentally handicapped. There, on that day, many things in my life took root. Other things were erased by the force of that memory. And the feeling that it is necessary to contribute to alleviating and making the life of man, the only being aware of the great gift of life, more bearable, became more intense and urgent. In 2023, on the 75th anniversary of the Universal Declaration of Human Rights, I proposed to the United Nations, through its High Commissioner for Human Rights, Mr. Volker Turk, the recognition as a human right of the prevention of diseases that cause irreversible neurological damage and requested their help in the processing of this new human right. We then asked all governments, institutions and scientific societies to support the proposal to declare as a human right the prevention through neonatal screening of pathologies in which irreversible damage can be avoided through early treatment. It is now necessary to promote a conscious citizenship that is not a spectator of what is happening, but an actor for the progressive and urgent elimination of risks that affect humanity without further remedy. At last, human beings are gradually recognising that they are equal in dignity and can express themselves freely. Now we can. Now we must. The creative capacity that distinguishes the human species encourages us and gives us hope.