Despite the prevalence of cloning in science-fiction books and movies, as of 2014, there is no evidence that a human being has ever been cloned. Scientists have cloned other animals, including sheep, mice, cows and even a rhesus monkey, but research into human cloning is hindered by unresolved ethical questions.
Reproductive cloning involves removing the nucleus from an egg cell and fusing the enucleated egg with another cell taken from the body of the egg donor. This fusion produces an egg cell with a genome identical to the donor. Donor and baby would be as similar as two identical twins, only with very different ages. While the scientific barriers to human cloning are probably surmountable, the ethical implications involved in creating a duplicate of another human being have led many countries around the world to adopt laws prohibiting reproductive human cloning.