Israeli scientists have presented a concept patent to use CRISP/Cas gene editing technology to produce modified chickens disallowing male offspring to hatch. The proposal is being touted as “more humane” because young male chicks from laying hens are currently slaughtered in the egg and chicken meat industries—being unsuitable for either industry.

Dr. Michael Antoniou and Claire Robinson point out the risks embedded in this hypothetical, unproven approach. If the technology doesn’t work perfectly, the founder breeder hens and their egg-laying daughters could produce a toxin at low levels in their bodies, leading to health problems. The male chicks would be deemed toxic, unsuitable for animal feed (a current use for them). The lethality gene could also escape into the environment or into bacteria, possibly harming humans, animals, or wildlife.

The EU Commission has labeled the hens and their eggs as not GMOs, so not requiring safety tests or labels.