Olympic long jump champion Greg Rutherford decides to freeze his sperm because of fears about the Zika virus at this year's Games in Rio de Janeiro.
Sperm have been made in the laboratory and used to father healthy baby mice in a pioneering move that could lead to infertility treatments.
The sperm of all 18-year-olds should be frozen for use in later life because of the risks attached with being an older father, a UK bioethicist argues.
