Researchers in China have successfully created healthy mice using only sperm from two male mice. These special mice later grew up and had babies of their own, making it the first time such a process has worked in this way.

Scientists at Shanghai Jiao Tong University carried out the experiment. They took sperm cells from two male mice and inserted them into a mouse egg. But first, they removed the nucleus (the part with the egg’s DNA). They then used gene editing to change the sperm’s DNA so it could develop into an embryo. This process is called androgenesis.

In total, 259 embryos were created and implanted into female mice. Only two of these embryos survived and grew into healthy male mice. Later, these mice mated with female mice and had babies, showing that mice with two dads can reproduce normally.

The study, published in the journal PNAS on June 25, explained why it is difficult to create life from two parents of the same sex. The researchers said, "In this study, we report the generation of fertile androgenetic mice." They added, "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."

Hope for the future, but not yet for humans

This discovery may give hope to same-sex couples or individuals facing fertility problems. But scientists say the process is still very complex and cannot be used in humans yet. Even if tried in humans, the baby would carry DNA from the egg donor (the woman) because of mitochondrial DNA, which is always passed down from the mother.

Also, the method used in this research raises ethical concerns about gene editing and reproduction.

Christophe Galichet from the Sainsbury Wellcome Centre in London said, "This research on generating offspring from same-sex parents is promising." But he warned, "[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."

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