Replicant: The Love of Dolly the Sheep

In a world where World War III happened, and the human population was decreased, scientific research was developed to address the problem: cloning technology. Chris and Seth are lead researchers of the lab that had successfully made the first perfect human clone in history. Even as best friends, the two harbor feelings for one another that goes beyond friendship. But Seth is soon to be engaged, leaving Chris to suppress his feelings to wish Seth happiness. To what ends will the two of them go?

Source: MangaPlanet