Scientists say they have created the world’s first human synthetic embryos from stem cells without using sperm or eggs.

Axar.az reports that these embryo-like structures lack organs such as a beating heart or a brain but include cells that would typically go on to form the placenta, yolk sac and the embryo itself.

“We can create human embryo-like models by the reprogramming of [embryonic stem] cells,” Professor Magdalena Zernicka-Goetz, of the University of Cambridge and the California Institute of Technology, said in an address on Wednesday at the International Society for Stem Cell Research annual meeting in Boston.

This research, yet to be published in a journal, raises legal and ethical questions, as many countries currently lack regulations looking at the creation and manipulation of synthetic embryos.

“Unlike human embryos arising from in vitro fertilisation (IVF), where there is an established legal framework, there are currently no clear regulations governing stem cell-derived models of human embryos. There is an urgent need for regulations to provide a framework for the creation and use of stem cell-derived models of human embryos,” CNN reported James Briscoe, associate research director at the Francis Crick Institute, in a statement.