A five-month-old boy has grown a five-inch tail.
Nuo Nuo was born with spina bifida, a rare spinal defect which leaves a gap in the spine.
Within days, his mother noticed a prominent tail beginning to form, which is still steadily increasing in size.
Distraught, she has implored surgeons in Changsha, China, to remove the growth but so far it has been deemed not possible.
The growth will have started within Nuo Nuo’s first month in the womb.
In the first four weeks, developing babies grow a structure called the neural tube. It is this that will eventually form the spine and nervous system.
In cases of spina bifida, the spinal column – the bone that surrounds and protects the nerves – does not fully close.
The exact causes are unknown, but several risk factors have been identified, the most significant being a lack of folic acid before and at the very start of pregnancy.
It affects one pregnancy in every 1,000 in Britain.
In most cases surgery can be done to close the defect.
However, damage to the nervous system will usually already have taken place, resulting in a range of symptoms, including paralysis and incontinence.