Dolly the sheep, the first mammal cloned from a somatic (body) cell, came into the world innocent as a lamb.
However, soon after the announcement of her birth in February 1997 (Wilmut et al., 1997) she caused panic and controversy.
Cloning mammals using embryonic cells has been successful since the mid-1980s (for a history of cloning, see Wilmut et al. Another technique to produce genetically identical offspring or clones is embryo twinning or embryo splitting, in which an early embryo is split so that both parts, when implanted in the uterus, can develop into individual organisms genetically identical to each other.
This process occurs naturally with identical twins.
Many countries or jurisdictions have legally banned human cloning or are in the process of doing so.
In some countries, including France and Singapore, reproductive cloning of humans is a criminal offence.
Strictly speaking, cloning is the creation of a genetic copy of a sequence of DNA or of the entire genome of an organism.
In the latter sense, cloning occurs naturally in the birth of identical twins and other multiples.
She represented a first undesirable and dangerous step to applying reproductive cloning in humans, something that many agreed should never be done.
Only a small minority thought it was permissible, or even morally obligatory to conduct further research into human reproductive cloning.