Human genetic engineering technology is more advanced in the contemporary world, attracting many people to support human enhancement. According to the Children's Medical Research Institute and Westmead Children's Hospital (2012), "more than 1,800 gene therapy clinical trials have been completed, are underway or have been approved worldwide", showing the growing importance of human engineering in society. According to the Oxford Dictionary (2006), human genetic engineering refers to the science of changing the behavior of a human being by modifying the information contained in their genes. Human genetic engineering can be divided into two categories, including gene therapy (pathological goal) and genetic enhancement (non-pathological goal), both of which enable self-improvement by optimizing attributes or abilities (National Institute for Research on the human genome, 2006). It can also be treated as a remedy for a loss of normal human function that may prevent or reduce a person's ability to function independently (Mayes, 2012). I have come to agree that seeking improvement is not an appropriate method for improving human well-being. Sometimes proponents seem to somewhat overestimate the merits of human enhancement and overlook its downsides and side effects. I believe there are real problems with seeking improvement, even if success is a given for what we assumed was not a given. Although the technological development of human engineering is increasingly mature, several concerns and problems still need to be overcome. In The Case against Perfection: Paper ......Welfare-Driven Distribution Models. Bioethics, 26(6), 296-304. Gene therapy clinical trials worldwide through 2012 - ... [J Gene Med. 2013] - PubMed - NCBI. (nd). Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/23355455Genetic Enhancement (2006). The National Human Genome Research Institute (nd). Retrieved from http://www.genome.gov/10004767 Mayes, S. (2012). Genetic enhancement: definitions, methodologies and the effect of parental attitudes. Penn Bioethics Journal, 8(2).McKean, E. (ed.). (2005). The New Oxford American Dictionary (2nd ed.). Oxford: Oxford University Press. Michael J. Sandel (2009). The Case against Perfection: Ethics in the Age of Genetic Engineering, Cambridge, Massachusetts: Harvard University Press. Chapter 5 (pp. 85-100) Turnbull, J., Bull, V., & Phillips, P. (2006). Oxford Word Power Dictionary. Oxford: Oxford University Press.