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Mice created from two dads

AP/Sam Ogden via The Whitehead Institute

This photo shows a mouse composed, in part, of cells that were reprogrammed to a stem cell-like state. New research has used these type of cells to create offspring from two fathers.

Reproductive scientists have used stem cell technology to create mice from two dads. The breakthrough could be a boon to efforts to save endangered species -- and the procedure could make it possible for same-sex couples to have their own genetic children.

The scientists, led by Richard Berhringer at the M.D. Anderson Cancer Center in Texas, describe the process in a study posted Wednesday in the journal Biology of Reproduction. Here's how it works:

Cells from a male mouse fetus were manipulated to produce an induced pluripotent stem cell line. These iPS cells are ordinary cells that have been reprogrammed to take on a state similar to that of an embryonic stem cell, which can develop into virtually any kind of tissue in the body.


About 1 percent of the iPS cell colonies spontaneously lost their Y chromosome, turning them into "XO" cells. These cells were injected into embryos from donor female mice, and transplanted into surrogate mothers.

The mommy mice gave birth to babies carrying one X chromosome from the original male mouse. Once these mice matured, the females were mated with normal male mice. Some of their offspring had genetic contributions from both fathers.

The study authors say their technique could be applied to animal breeding efforts, so that two males with desirable traits could be crossed without mixing in traits from females. "It is also possible that one male could produce both oocytes (eggs) and sperm for self-fertilization to generate male and female progeny," the team writes. This could help save an endangered species that no longer had females to mate with, for example.

In the future, scientists may be able to create human eggs from male iPS cells in vitro, allowing them to eliminate the need for the intermediate offspring, though a surrogate mother would still be needed to carry the two-father pregnancy to term.

With a variation of the technique, "it may also be possible to generate sperm from a female donor and produce viable male and female progeny with two mothers," the researchers write.

The research joins a long list of stem cell breakthroughs with mouse models. Check out the stories below to learn what else researchers have done with mice.


John Roach is a contributing writer for msnbc.com. Connect with the Cosmic Log community by hitting the "like" button on the Cosmic Log Facebook page or following msnbc.com's science editor, Alan Boyle, on Twitter (@b0yle).