DNA From a Single Male Can Create Both Mom and Dad

One male mouse supplied the genetic starting material for both halves of a breeding pair. Researchers cloned him twice, once as male and once as female, and the two clones mated to produce healthy pups.

A team at the University of Yamanashi and RIKEN BioResource Research Center in Japan did it with a CRISPR-based technique called Y-CUT. Male mouse cells normally carry an X and a Y chromosome. Y-CUT damages the machinery that keeps the Y chromosome in place when a cell divides, causing the chromosome to be lost.

What remains is a cell with a single X chromosome. In mice, that can develop into a female.

The researchers used the technique to create female clones from male mice. Those females grew normally and were fertile. Female and male clones made from the same original male could then reproduce with each other and produce healthy offspring.

Y-CUT also worked on frozen male cells, which could make it useful when conservationists have stored genetic material from males but no females. It does not solve the harder problems of genetic diversity, compatible egg donors or surrogates. Mice have another advantage: females with only one X chromosome can still be fertile. Many mammals cannot pull off that trick.

The research remains a bioRxiv preprint and has not yet been peer-reviewed.

For mice, the traditional requirement for two genetic donors was undone. One male genome supplied the raw material for mom, dad and the next generation.

Read the full story at MIT Technology Review, August 12, 2026

Hot Take: Noah needed two of everything. Geneticists are apparently reviewing the headcount.