Biologists are working to overcome a number of issues that prevent cloning.
The way cloning basically works, is to replace the nucleus of an early embryo cell with that of an adult animal. Then the embryo cell is inserted into a mother where it will develop normally. However, there are issues which prevent the clone from growing healthily.
When an animal develops they are differentiating their cells so that each can perform a different job. This is done by tightly winding some of the chromatin together so that it cannot be transcribed. When this differentiated cell divides, its daughter cells inherit the differentiation. The reason this causes problems for cloning is because when you take the nucleolus from a tissue sample to are sampling differentiated DNA. So even though 100% of the DNA is there only, for example, the DNA for skin cells is used, so an entire organism cannot be grown.
When an organism prepares to divide naturally there is a process for reverting the differentiation in order to create gametes. Therefor when people attempt to clone an animal they do their best to mimic the process. However, this does not work perfectly and is the reason that all clones people have been able to create to date have been deformed and not lived out the normal life span. The Famous sheep dolly is an example where she was at first thought to be a successful mammal clone she ended up having a particularly short life.
But the situation is not hopeless! Over the years, scientists have made massive progress toward cloning from creating the first diploid cells in a lab setting to eventually successfully cloning frogs. Then cloning the first mice. It only took about fifty years to make it this far so it isn’t unreasonable to suspect the advances in science will be there during our lifetime.
However, the issue of ethics is still prominent. For humans to clone another human makes for a myriad of possible controversies. One that arises constantly in the biological field is whether or not we are playing god. But assuming we as a race have the right to the power of cloning, the question remains, should we use it?
If we are cloning humans the human to be born a clone will always have no say in the matter, and because the clone will be created for some purpose, it may damage the child’s sense of worth. For example, the first clone children will be born for the advancement of science and being a lab born and raised child may prevent them from ever feeling like they fit in.
The issue is, hypothetically, even after cloning children is a tried and reliable practice, the main reasons a child would be cloned would be to fulfill a predesigned purpose. Like replacing a deceased loved on or matching the athletic ability of an adult. In both these situations, those who decided to create the clone are expecting something out of them even before they are born, which could be stressful for the child.
Although cloning humans would be a massive advancement to mankind, I do not believe it should be one commonly practiced for moral reasons.