Hong Kong: A group of leading scientists has declared that it’s still too soon to try making permanent changes to DNA that can be inherited by future generations, as a Chinese researcher claims to have done.

The scientists gathered in Hong Kong this week for an international conference on gene editing, the ability to rewrite the code of life to try to correct or prevent diseases.

Although the science holds promise for helping people already born, the scientists said Thursday that it’s irresponsible to try it on eggs, sperm or embryos because not enough is known yet about its risks or safety.

The conference was rocked by the Chinese researcher’s claim to have helped make the world’s first gene-edited babies, twin girls he said were born earlier this month.