Scientists at Stanford University in California found the right cocktail of chemicals and vitamins to coax the cells into becoming eggs and sperm, the Daily Mail reported. The sperm had heads and short tails and are thought to have been mature enough to fertilise an egg. The eggs were at a much earlier stage but were still much more developed than any created so far by other scientists.

It paves the way for a cure for infertility and could help those left sterile by cancer treatment to have children who are biologically their own. But it raises a number of moral and ethical concerns. These include the possibility of children being born through entirely artificial means, and men and women being sidelined from the process of making babies.