Those who favor this, always think of how noble, virtuous humanity is, and want to use it to cure genetic diseases.
The dark side is people will use it to create genetic enhanced athletes, looks.
It's plastic surgery gone wild, and steroid enhancement without side effect.
China's one child policy has had a terrible impact, because many girls were aborted, throwing china's man woman ratio horribly wrong.
S Korea is already making glow in the dark dogs.
http://www.wired.co.uk/article/tegon-the-glow-in-the-dark-dog
Note that the article is 5 yrs old, a lifetime in medical advancement now.