Even if it could work one day, I still feel it is too scary on humans

Yea, I defiantly agree with you there; I don't think science should over be manipulating our bodys. The ONLY exception in my mind is when somebody has a medical condition/issue and science is manipulating his/her body to make it more normal.
I'm not surprised at all if manipulation with the human body begins. But it goes beyond understanding when genetics try to program a human child even at the embryo stage to see a particular child, sex, hair and skin color, and much more. This not normal.