Further steps towards artificial eggs and sperm

Human embryonic stem cells have been coaxed in the lab to develop into the early forms of cells which eventually become eggs or sperm, UK researchers have revealed.

Work by several groups has shown that a tiny proportion of human embryonic stem cells (ESCs) spontaneously develop into primordial germ cells when allowed to differentiate in a dish. In this latest study, Behrouz Aflatoonian and colleagues at the University of Sheffield, produced primordial germ cells which began to express the proteins characteristic of sperm cells, while others resembled eggs.

But there is still a long way to go before doctors can even think of trying the technique in people. The researchers have not proved, for example, that the cells that express sperm proteins have divided properly and possess only one set of chromosomes like normal sperm.

The team presented their results at a meeting of the European Society for Human Reproduction and Embryology (ESHRE) in Copenhagen, Denmark, on Monday.

Ultimate aims

The dream of growing sperm and egg cells outside the body remains exactly that for the moment. Although progress has...