Two people that have had surgery to look beautiful are going to marry, fall in love and start a family. And then be really surprised when their baby comes out fugly.
Adult genetic engineering would not be inheritable. Your gonads produce variations of genetic material based on their own blueprints (which come from you parents, not your genes).
How would you genetically engineer an adult, or anyone who is born? It would require changing the DNA of all cells, as well as executing those changes.
And not having the immune system reject all the changes as soon as its own DNA starts changing.
It has the same problem as upgrading a distributed system that checksums all incoming protocols against its own binary. As soon as the binary changes, everything else gets rejected, and the system grinds to a halt.
