Advent of Recombinant DNA Technology has made it possible to detect defective genes and replace them with “good” genes. Consequently the genetic diseases, which result on mutations can now be cured. The first successful gene therapy experient was done on a 9 year old Indian girl Ashanti in 1990 in USA, who was suffering from a fatal immunological disease – SCID, which is caused by a mutation in ADA gene. The scientists introduced the the “good” copy of the gene in her body and were successful in curing her of this fatal disease. This encouraged other researchers and now several methods are being tried to cure genetic diseases.