Nothing in the nine months of the incubation of Danel and Maria suggested that they would become immediately famous.

They were ordinary twins in a healthy pregnancy, able to feel each other's presence but not physically touch due to each being in a separate amniotic sac, according to Basque daily Diario Vasco.

The babies were in a breech position so the decision was made by doctors at Gipuzkoa Hospital in the Basque Country to deliver them by caesarean section.

As soon as they were born, the babies were placed side by side in a thermal cot.

It was then that doctors and nurses became captivated by what they saw: the newborn siblings linking fingers and holding hands.

The twins' father, Mario said: "They [the staff] asked for my mobile phone because they wanted to take a beautiful photo."

In the end they took three.

The images show Danel and Maria turned away from each other, still unable to see, still awaiting the first touch from their mother but already clasping their hands together.

"I've seen a lot of births and I've seen a lot of newborns but I've never seen that before," said Dr. Rodríguez who asked the parents for permission to hang the photo in his office.

Dad Mairo says that his babies, now four months old, "don't hold hands any more but when they see each other they smile."

"The day they held hands they signed a contract to be together forever."