It's similar to the dilemma about cloning, but on an even deeper level. Suppose someone had a good friend; the best one they'd ever had in the world, and that person died.

What if they were able to clone that person? They would have the same face and voice, maybe even a few similar mannerisms and quirks, however that clone is still their own person. They may grow to have a similar relationship to the one held with the donor of their DNA, but it will never be exactly the same. To heap that kind of expectation on someone else would be unfair.