In A First, Scientists Create Healthy, Fertile Mice From DNA Of Two Fathers

Researchers in China have achieved an extraordinary feat in reproductive science by creating healthy mice with two fathers that grow up to have babies of their own. The researchers at Shanghai Jiao Tong University inserted two sperm cells, one from each father, into a mouse egg whose nucleus had been removed.

They used gene editing techniques to reprogram parts of the sperm's DNA so that an embryo could develop in a process called androgenesis. Out of 259 embryos implanted into surrogate female mice, only two survived and grew up healthy. Both males later mated with female mice and had babies, proving that mice with two dads can reproduce.

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This study helps explain why creating a life for two parents of the same sex has been challenging. The findings also shed light on genomic imprinting, where genes behave differently depending on whether they come from the mother or father.

"In this study, we report the generation of fertile androgenetic mice," the researchers said in their paper, published in the journal PNAS on June 25.

"Our findings, together with previous achievements of uniparental reproduction in mammals, support previous speculation that genomic imprinting is the fundamental barrier to the full-term development of uniparental mammalian embryos," they added.

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The research gives new hope to same-sex couples or individuals who are facing fertility challenges, but there are limitations as the process is complex and not feasible for humans at present. Even if attempted in humans, the baby would technically have DNA from a third person - the woman who donates the egg, due to mitochondrial DNA.

The process also uses techniques that raise ethical questions regarding genetic manipulation and reproductive rights.

Christophe Galichet, research operations manager at the Sainsbury Wellcome Centre in London, highlighted the low success rate.

"This research on generating offspring from same-sex parents is promising," Galichet told New Scientist. He was not involved in the experiments.

"[But] it is unthinkable to translate it to humans due to the large number of eggs required, the high number of surrogate women needed and the low success rate," Galichet added.