Biotechnology is generally defined as the modification of biological materials and organisms for specific uses or purposes. Examples include genetic engineering, drug-delivery systems, and animal-human hybrid embryos. While some of these technologies hold the promise of improved treatments and therapies for disease, the ethics of manipulating biological organisms (especially human organisms) is called into question for certain biotechnologies.  Articles in this section examine the ethics surrounding biotechnology, including the ends for which these are pursued, the effects on our understanding of what it means to be human, and the subsequent impact on our common humanity. For biotech discussions particular to cloning and stem cell research, please see the respective pages addressing those issues.