Somatic Cell Nuclear Transfer (Therapeutic Cloning)
    In genetics, somatic cell nuclear transfer is a technique for cloning.

What happens

The somatic cell is fused with the enuclated oocyte.

Problems

The stress on both the cell and the nucleus are enormous, which leads to a high mortality rate of recipient cells. As the procedure currently cannot be automated, but has to be performed manually under a
microscope, somatic cell nuclear transfer is very resource-consuming.

As the donor cell is a somatic cell, it has to be artificially "activated" to start working as a fertilized egg cell, thus growing into a whole organism. The biochemistry involving this activation is far from understood.

Also, not all genetic information of the donor cell is transferred. DNA of organelles (mostly mitochondria) is not moved together with the nucleus, but remains that of the recipient cell. This procedure, as it is very ethical, has only been performed on mice.