Yes Mirror? No Mirror? See for yourself!

The world we live in today is based on many norms and rules we have to comply to be neutral in the society. But these rules only give us distinction in the law and order parts of society. To maintain a stable relation with oneself and society, you must also obey the moral laws. You are who you are, and only you choose whether or not to follow your beliefs.
I believe that genetic engineering is against any ethical or moral rule. Having said that existentialism is based on who you are and you must act according to it, having another person to act the same way as you do would be acting as another person, because no one is exactly the same. People in the world that agree with genetic engineering couldn’t be existentialist because they would be saying that acting as another person, although very similar to you, is accepted. Existentialism states that if you are yourself, then you don’t have any other influence in your character than that adopted by society. Having another person that is equal to you is against the ethical rule of existentialism.
The cloning of a human is not ethical, at all, because you are who you are and nothing can change that. Human genetics are very complex, thus giving many other options as to change the way the clone will act. If having a person equal to you in all physical traits, and acted in a different manner as you do, then genetic engineering would be ethical.