German scientists have achieved a breakthrough in the field of fertility treatment by using human bone marrow to create early-stage sperm cells.

The research, which was published in the academic journal Reproduction on Friday, reported that scientists were able to create spermatagonial cells, but were unable to get the cells to develop into fully functional sperm. They warned that it could take more time before they are used in fertility treatment.

CBC news quotes lead Professor Karim Nayernia, as saying, "Our next goal is to see if we can get the spermatagonial stem cells to progress to mature sperm in the laboratory and this should take around three to five years of experiments."

Researchers took bone marrow from male volunteers and isolated stem cells previously found to grow into other body tissues such as muscle.

"We are very excited about this discovery," Nayernia said of his new research paper.

Experts are hoping that the new research could help in fertility treatment for men in future and added that if female bone marrow is also able to produce sperm cells, it raises the possibility that women would be able to pass on their genetic material through manufactured sperm.