A Chinese reproductive biologist said in Beijing Wednesday he is not optimistic about the clinical use of artificial sperm to counter infertility.

Han Chunsheng, a researcher with the Chinese Academy of Sciences Institute of Zoology, said in an interview with Xinhua, "There are still problems in producing artificial sperm, and nobody can predict how long it will take before the technology can be employed in clinical practice."

Karim Nayernia, a researcher at Newcastle University in the United Kingdom, published a paper in the July 10 issue of the journal Developmental Cell, announcing that his team had bred mice with mature sperm developed from embryonic stem cells. It is the first time that live baby animals have been produced with this kind of artificial sperm.

They believe the technology may help infertile men have children.

"Another team produced artificial sperm without tails two or three years ago," Han said, adding that the new development was not really a breakthrough because although the sperm had grown tails, they still could not swim and had to be injected into the mouse eggs.

Han said that another key topic in infertility research is cultivating stem cells through nuclear transfer, which is still in the animal experiment stage.

In the past, Han and his team carried out research similar to that of the British scientists but gave it up because of insurmountable technical difficulties.

Now they are focusing on making sperm from spermatogonial stem cells, an easier process because spermatogonial stem cells are the only ones that can turn into sperm cells.

No achievements in their new research have so far been reported. "It's a frontier technology and it will be years before it bears fruit, but we will keep trying," Han said.

Source: Xinhua