No, you can't. Not without hacks (Action Replay). You can use Pokesav. This controversial program will allow you to change almost anything of your save file. Remember though, that many despise users of Pokesav, as it is a program that allows you to do in minutes what legitimate players would take thousands of hours to do (eg. getting a team with perfect EVs, good IVs and perfect natures).
Chat with our AI personalities
What do you mean how do you make a shiny Pokemon stay shiny if you get a shiny Pokemon it stays shiny ok!
In the second generation, you had a 50% chance of getting a shiny Pokemon this way, but in the 3rd generation onwards, chances were decreased and you did not have a better chance of getting a shiny Pokemon by using this method. Additionally, you won't know if the baby Pokemon will be shiny until it hatches because eggs containing shiny Pokemon do not look any different from eggs that contain non-shiny Pokemon.
there is non
Your Mom! Catch shiny Pokemon like a non noob by chaining!
No, the egg will not be shiny. However, it is possible that the egg will hatch into a shiny Pokemon, but the chances of getting a shiny Pokemon from the egg are not any higher than they would be if the ditto were not shiny.