“Look, Dad – no Mum!” was the headline in one
of Nature’s blogs. Reproductive scientists in a Texas research centre have
produced male and female mice from two fathers using induced pluripotent stem
They claim that the achievement of
two-father offspring could help preserve endangered species, improve livestock
breeds, and advance human assisted reproductive technology. It also opens the
provocative possibility of same-sex couples having their own genetic children,
the researchers noted in a headline-grabbing aside.
However, the procedure is so complicated
that it is unlikely to have any practical application for some time.
The scientists used cells from a male (XY)
mouse fetus to produce an iPS cell line. About one percent of iPS cell colonies
grown from this XY cell line spontaneously lost the Y chromosome, resulting in
XO cells. The XO iPS cells were injected into embryos and then transplanted
into surrogate mothers. These gave birth to female XO/XX chimeras having one X
chromosome from the original male mouse fibroblast.
The female chimeras, carrying oocytes
derived from the XO cells, were mated with normal male mice. Some of the
offspring were male and female mice that had genetic contributions from two
This experiment does show that iPS cells
could be used for ethically controversial purposes. It shows that it might be
possible to generate human eggs from male iPS cells. Of course, a surrogate mother
would still be needed to carry the two-father pregnancy to term.
The procedure could work the other way
around. "It may also be possible to generate sperm from a female donor and
produce viable male and female progeny with two mothers," say the researchers.
The authors of the study, published in the
journal Biology of Reproduction, caution that the "generation of human iPS
cells still requires significant refinements prior to their use for therapeutic
purposes." ~ Eurekalert,