Ethics of bioengineering organs and tissues.

Tissue-engineered medical products are now entering the clinical testing phase of development. Therefore, an open discussion is warranted regarding ethical issues that may arise as these novel 'combination' products move forward, such as when to conduct clinical trials, how to regulate such trials, when and how to responsibly introduce these strategies into clinical practice and how to maintain a positive public perception of the tissue-engineering field as a whole. These issues are discussed, and recommendations are provided for conducting first-in-human clinical studies.