Milwaukee ? Scientists have gotten stem cells from monkey embryos that were grown from eggs alone no sperm boosting the chances that human stem cells can be obtained the same way, without destroying normal, viable embryos.

The hitch: Only fertile women would benefit. The technique doesn’t work for males or females too young or old to make eggs.

The work was done by Advanced Cell Technology, a Massachusetts biotechnology firm, and researchers at Wake Forest University, the Sloan Kettering Cancer Center and the Mayo Clinic. It was published Friday in the journal Science.

“What it tells you is we can definitely isolate these stem cells from embryos and can activate them” to form various tissues, said Jose Cibelli of Advanced Cell.

As for achieving the same in humans, which Advanced Cell has been attempting, “It’s just a matter of time. You can see that it’s feasible,” he said.

The technique is called parthenogenesis, in which an egg is stimulated with chemicals and an electrical charge to divide and grow, as it would do naturally if it had been fertilized by sperm.

These “single-parent” embryos parthenotes, scientists say they should be called aren’t capable of developing into an organism as fertilized eggs are. Instead, they’re grown in a lab dish for about a week until they produce stem cells that can be removed.

It’s too soon to tell whether these cells will work like embryonic stem cells, master cells that form all the tissues of the body and that scientists hope to use to treat diseases.

“There are reasons to believe that the derivatives of these (parthenote) cells would not be entirely normal because a specific class of genes would be expressed incorrectly,” said University of Wisconsin-Madison scientist James Thomson, who was the first to isolate embryonic stem cells from monkeys in 1994 and in humans in 1998.

It has to do with genes that remain dormant, something called imprinting, said Thaddeus Golos, another researcher at the University of Wisconsin.

“Imprinting means that although we have two copies of all of our genes, only the copy from one parent is active. … So presumably, cells that are derived from these parthenogenetic stem cells will not be expressing some of those genes,” Golos explained.

The experiment originated at Wake Forest, which is using primates to research alcoholism and its treatment. Scientists wanted “to see what the promise of stem cells might be in reversing the damage to the liver” as an alternative to liver transplants, said physiology expert Kathleen Grant.