Scientists have made a major breakthrough that could soon see human sperm grown in the laboratory.
The development opens up the possibility of infertile men being able to father their own children rather than using donor sperm.
Researchers in Germany and Israel were able to grow mouse sperm from a few cells in a laboratory dish.
In a world first a team headed by Professor Stefan Schlatt, at Muenster University in Germany, were able to grow sperm by using germ cells. These are the cells in testicles that are responsible for sperm production.
Scientists grew the sperm by surrounding the germ cells in a special compound called agar jelly to create an environment similar to that found in testicles.