In general human enhancements differ from genetic therapies in that they concern the alteration of inherited traits that do not cause disease.
Nongenetic enhancements are common in contemporary medical practice: many middle-aged people undergo surgery to reduce facial wrinkles or replace lost hair; men with erectile dysfunction use drugs to facilitate sexual intercourse; and some parents obtain human growth hormone to increase their children's height.
Ethicists and the general public hold varying opinions on whether it is advisable or desirable to use genetic technology to enhance human qualities, e.g., the selection of the sex of their offspring, or the enhancement of their children's musculature, intelligence, or behavior. Some genetic enhancements may have dual functions: genetic alterations that treat muscular dystrophies might also be used to enhance the athletic abilities of healthy individuals. These intersections between health and cosmetics provoke the thorniest ethical questions: Should humans try to optimize selected characteristics of their species through genetics? Who will pay for such enhancements? Will they be available only to those with the wealth to purchase them? Will they be restricted in some nations because of religious or social concerns and available in others where these considerations are not shared? These and other problems remain to be addressed by ethicists, scientists, families, and society at large.