While many find it unacceptable to use erythropoietin for increased endurance in sports, most of society finds its use perfectly acceptable for treatment of chronic anemia (Kiuru & Crystal, 2008, p. 330). Another example is the use of growth hormone. Growth hormone can be used to become taller or stronger for social, cosmetic, or athletic purposes but it is considered inappropriate to use them for this purpose. Society, however, finds it perfectly acceptable as a treatment for short stature due to a growth hormone deficiency or Turner's syndrome (Kiuru & Crystal, 2008, p. 330) The problem with that approach to the ethical side of enhancement can be explained with the use of an anecdote by Nils Holtug (2011), an associate professor at the University of Copenhagen: Johnny is a short 11-year-old boy with documented growth hormone (GH) deficiency resulting from a brain tumor. His parents are of average height. His predicted adult height without GH treatment is approximately 160 cm (5 feet 3 inches). Billy is a short 11-year-old boy with normal GH secretion according to current testing methods. However, his parents are extremely short, and he has a predicted adult height of 160 cm (5 feet 3 inches). .
(141).
As it currently stands, Johnny would be given growth hormone as a treatment, but if Billy is given growth hormone it would be considered an enhancement because Billy's height is due to his genetics and not a disease. Everything else being equal, Johnny and Billy are "equal competitors" (Holtug 141) because they have the exact same disadvantage if neither of them receive growth hormones. Considering this, they – again if everything else is equal – have equal opportunities. Because both cases are so similar in terms of equality and opportunity, "one would expect the normal function model to treat these two cases alike" (Holtug 141). Additionally, many of these treatments have an effect on athletic ability.