Meet Zhong Zhong and Hua Hua. They're about to dominate the world press for quite some time. It's not just because they're cute. The two monkeys are the first ever primates to be cloned, using the procedure that produced Dolly the Sheep 20 years ago.

In 1997, Dolly became a sensation as the first mammal to be cloned with DNA taken from an adult of its species. Since then, the technique has been used to clone more than 20 different animal species, including dogs, pigs and cats.

But not primates, until now.

The Chinese Academy of Science announced this breakthrough in a paper released Wednesday by the journal Cell.

The cloning process begins with a monkey egg and a fetal monkey cell. Researchers take the DNA from the nucleus of fetal monkey cells and put the genes into monkey eggs that had their own DNA removed . The reconstructed eggs produce embryos, which are put into the wombs of surrogate female monkeys, producing cloned baby monkeys with the same genetic background. It's the first time this technology, which is called somatic cell nuclear transfer, has been used to clone any close relatives of humans.

But the process is still very inefficient. It took 127 egg cells to get the two babies

SUN QIANG, DIRECTOR NON-HUMAN PRIMATE FACILITY "We were looking after them like treasures in hope of the newborns. Fortunately, they were born at the end of 2017 and very healthy."

Experts say it should greatly help medical and scientific research.

POO MUMING, NEUROSCIENCE DIRECTOR CHINESE ACADEMY OF SCIENCE "Now for many human diseases that are genetically based, if we can produce a cloned animal with identical genetic background and then edit in specific genes that are related to a human disease. Then we can produce a large number of animals or monkeys for medical purposes, for testing a drug, and for developing approaches for therapy."

But it's also likely to reawaken a long-dormant debate that sprang up when Dolly's birth was announced in 1997: How close are we to cloning a human being?

POO MUMING, NEUROSCIENCE DIRECTOR CHINESE ACADEMY OF SCIENCE "In principle you can clone humans. Maybe there are more technical difficulties but in principle it should not be a problem. But the reason we do the monkey cloning is purely for medical purposes. We want to develop clones to help human health."

Monkeys are biologically more like humans than other lab animals like rats, making them a perfect model for research relevant to humans, such as the study of brains. The third baby monkey is on its way this month, and more will come this year.