You end up with an aristocracy that can afford to have better superhuman children meanwhile the plebs can't afford it. And it would perpetuate itself. Bye tabula rasa in birth and death.
there will always be people who have an advantage over others, the majority simply comes from where you were born followed to whom to you were born too.
The real fear is likely that some will make choices that are not politically correct, it is certain this would happen in non Western countries.
Consider the ethical implications of the job they pay you to do. Always. Who will be benefiting from my work? Who might be harmed by it? Can I trust my employer to protect--or even just accurately represent--my own interests?
Do not take jobs that grant more power to the powerful at the expense of the weak.
My litmus test for human gene-mod technology will be whether I will ever be able to repair my phi-GULO pseudogene, to restore the mammalian ability to synthesize ascorbates (vitamin C) in the liver, without needing to get permission from anyone to do it, and without paying more than a year's salary or using more than one garage of space on the equipment. If I can do that, this particular genie cannot be re-bottled.
And you can bet I'd be selling CKGGRAKDC-GG-D(KLAKLAK)2 under the table, too.