I don't know much on the last part, but I do know the basics.
Doctors in China (It's outlawed in the US) are trying to change genes in babies (and eventually want to do children and adults) that could potentially cause harm to them. They say that they can change a bad disease for example, by taking one gene out and adding a new healthy one where the old one was.
Epigenetics doctors (lawful in the US) say that they can change family history by switch a gene off or on. (Let's say your relative has the Alzheimers disease. Doctors can make that go away in a future descendant by telling them to have better eating habits and other things that are healthy for you.)
I believe gene editing is evil. While maybe you're fixing the problem of the disease, you may be allowing some other sort of bad thing to enter the body through someone other persons genes.
I also think it's going to go down much further down the road. People are going to be doing to change hair and eye color and stuff like that. I think most us can agree that that is not what God intended.
Now my take on epigenetics...
While it may seem like a healthy thing to do, it's a lot like gene editing. You're trying to switch something bad into good by sorts of practices. Yeah, it may sound fine to you, but I just believe it's bad anyway.
I'm 98% certain that gene editing will soon be legal in the US someway, somehow. When it does you can look back and remember that some kid named Jacoby predicted it would happen.
So yeah. That's my take on the matter. Hope that answers your questions. (You too, @Iliara_Mustardtop and anyone else who wondered.)