what exactly does gene therapy do?

Just to clarify some stuff: gene doping is the insertion of a normal genetic material into a human cell in order to replace an abnormal genome. This is usually done with a artificial virus that is carrying some type of human DNA. Once the DNA has been injected into the cell, it could correct the genetic mistake. the consequences to it is that it would be very hard for someone to get it out of their gene pool.
http://www.articlesbase.com/alternative-medicine-articles/gene-therapy-types-of-gene-therapy-461354.html

the two genes are

oh and for those who wants to know, the gene that they changed/inserted to the monkey was a pair of opsin gene. one codes for green in the retina while the other one red. thus if one is missing then they are not able to figure out a certain color thus they become color blind. the can cause major problems in our society since we our stop light are in red and green, if some one can't recognize them than they can't drive.

colorblindness can be cured?

so it turns out that gene therapy has cured the colorblindness of a monkey at the university of Washington in Seattle. there seems to be high hopes for human treatments as well. this goes to show that gene therapy should be populerized since it can help improve many people's lives.check it out athttp://news.softpedia.com/news/Gene-Therapy-Cures-Color-Blindness-121877.shtml

gene doping

Gene doping technology have been developed since the 90s, however most people have been against it especially for athletic purposes. should gene therapy be available popularized for medical uses though? what has it done for our society now? has it been very successful?