Babies could one day be made without the need for a female egg, if new research is anything to go by.
A group of scientists from the University of Bath reported in Nature Communications that they had successfully created baby mice by tricking sperm into fertilising fake eggs.
The success of the groundbreaking experiment could one day pave the way for human babies to be created without an egg.
One of the scientists who worked on the experiment, Dr Tony Perry, told the BBC, "This is the first time that anyone has been able to show that anything other than an egg can combine with a sperm in this way to give rise to offspring.
"It overturns nearly 200 years of thinking."
In the experiment, researchers used chemicals to trick an unfertilised egg into becoming a pseudo-embryo, before injecting it with sperm.
Results showed that one in four of the embryos led to a successful birth, with the resulting baby mice having a normal life expectancy and even giving birth to their own pups.
"One possibility, in the distant future, is that it might be possible that ordinary cells in the body can be combined with a sperm so that an embryo is formed," said Dr Perry.
This could mean that two men would be able to create a baby, by combining normal cells from one with sperm from another. A man might even be able to have his own child completely independently, creating a non-identical twin to himself by combining his own cells and sperm.
This latest research follows the news that scientists in China were able to create healthy mice using sperm made from stem cells and an egg, suggesting that one day babies could even be made without the need for an egg or sperm.