The parents of a baby boy born with a rare congenital condition in China are seeking help for him to undergo surgery.

Four-month-old Hong Hong, from Pingjiang County in Hunan province, suffers from polydactylism, which has afflicted him with 31 fingers and toes.

He has two palms, no thumbs and 15 fingers on both his hands, and eight toes on each foot.

Hong Hong's condition was inherited from his mother, a factory worker in the southern Shenzhen city who also has polydactylism.

The condition affects humans, dogs and cats and the extra digits are usually removed surgically.

His father, Mr Zou Chengling, told People's Daily: "My wife has one extra finger and toe on each of her hands and feet, so we were worried that our child would inherit the condition.

"But after going to three big hospitals in Shenzhen, doctors found no birth defects on our son during scans."

Yet when Hong Hong was born, both parents were shocked to discover that he had polydactylism.

Doctors have told the couple that Hong Hong's condition can be treated once he is old enough to undergo anaesthesia, but the surgery will have to take place while he is still a baby, before the bones are set.

Others informed Mr Zou that surgery could be more complicated than originally thought, reported CNN, as the baby would also need reconstructed thumbs after removing his extra toes and fingers.

Opposable thumbs are crucial for grasping objects.

Hong Hong's surgery, however, is estimated to cost up to 200,000 yuan (S$41,800).

Over 40,000 yuan has been raised through online crowdfunding efforts, although they have been suspended after Mr Zou was criticised by some for attempting to raise money on the Internet.