When Dolly the sheep was cloned the cell nucleus of an adult sheep was put into a sheep egg cell and the egg cell was put into the womb of another sheep. Dolly developed with all the DNA from the sheep that contributed the cell nucleus and was therefore genetically identical to this sheep.
Human cloning would/will be the same thing as happened with Dolly. The nucleus of the cell from one human would be put into a human egg cell while the nucleus of that cell would be removed. Any embryo formed from that would be implanted into the womb of a foster mother. If a baby was born that baby would be like a younger identical twin of the donor who contributed the cell nucleus. Embryo implantation is successful and routinely done but no scientist has successfully created a human clone.
- A high proportion of cloned animals die or are disabled. Doing that to humans will not be acceptable unless/until the scientists are sure any baby is likely to be healthy.
- Cloning Einstein would be wonderful if it could be done. Cloning Hitler? Well.