Mixing genetic material from same-sex couples runs the risk of the babies receiving two sets of “imprinted” genes.
So the study used haploid embryonic stem cells, which resemble “primordial germ cells, the precursors of eggs and sperm,” said co-senior author Baoyang Hu.
They then altered the genetic makeup of the cells, deleting “imprinting regions” to effectively mimic the “shutting off” process in normal reproduction.
In the case of the female mice, three “imprinting regions” were deleted from the stem cells, which were then injected into the eggs of another mouse.
In the case of the male mice, seven “imprinting regions” were deleted and the cells were injected into a mouse egg along with sperm from a second mouse “father.”
The nucleus of the mouse egg was removed, meaning there was no female genetic material left and the fertilised egg was placed in a surrogate mouse.
Using two sets of female mice DNA, with gene manipulations, the scientists produced 29 babies from 210 embryos, which lived to adulthood and reproduced normally.
But the mice produced from two male sets of genetic material survived only 48 hours, with the researchers planning further study as to why the process did not work.