The list of such diseases is long - it includes diabetes, hypertension, haemophilia, thalassemia, Down's syndrome and even certain cancers.
For now, the scientists had removed a mutated gene from a human embryo, which, they said can cause heart attack.
The scientists deleted the faulty genes using CRISPR CAS - the most versatile tool in bio-technology which can add and remove parts of a DNA sequence with pin-point accuracy. The healthy embryos were then allowed to grow further - but only for a few days.
An account of the research, complete with photos of the multiplying cells, was published in the prestigious British journal "Nature". For obvious ethical considerations, the embryo was not implanted in any woman.
The scientists are well aware of the ethical issues their latest research has thrown up. The possibility of scientifically modifying humans - the object of some of the most twisted research by the Nazis - had re-surfaced after the huge strides in gene research and reproductive technology made over the last few decades.
"Gene editing is still in its infancy... it is crucial that we continue to proceed with the utmost caution, paying the highest attention to ethical considerations," said Juan Carlos Izpisua Belmonte, a professor in Salk Institutes Gene Expression Laboratory and a co-author of the paper.