Scientists at the University of Yamanashi and Riken BioResource Research Center used CRISPR to excise the Y chromosome from male mouse embryos, producing female animals genetically identical to their male source. The goal is conservation: when a species is down to its last few individuals, this technique could expand reproductive options. Reproductive biologist Takashi Ishiuchi co-led the work and called it something close to science fiction.
Cloning's track record is already strange. Dolly the sheep arrived in 1996. Pet cloning now runs tens of thousands of dollars per animal, with Barbra Streisand and Tom Brady among known clients. Bioethicist Jessica Pierce calls dog cloning 'the exploitation of the canine underclass,' a line worth sitting with given the egg donors and surrogates the procedure requires. On the conservation side, San Diego Zoo alone holds cryopreserved cells from over 1,300 species. Those samples produced clones of black-footed ferrets and Przewalski's horses. In 2009, Spanish researchers cloned the extinct Pyrenean ibex from decade-old skin cells, generating 439 embryos to get one live birth. She died minutes later from a lung defect, making the Pyrenean ibex the only species documented to have gone extinct twice.
The outer edge of the field is where the reading gets uncomfortable. A biotech startup founder has pitched brainless human clones grown as personal organ reserves, a concept MIT Technology Review's Antonio Regalado documented in March 2026. No confirmed human clone exists, as far as anyone knows. The full article traces the science from Dolly to de-extinction to that organ-sack pitch in a single, unsettling line of progression. Read it to understand how quickly the field's ambitions have outpaced any consensus on limits.
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