British scientists claim they have made the first-ever synthetic human sperm.
The sperm was grown in a laboratory using embryonic stem cells and can swim, have tails and share other characteristics of real sperm.
The research could be a breakthrough treatment for male infertility, according to The Guardian (U.K.).
"This is an important development as it will allow researchers to study in detail how sperm forms and lead to a better understanding of infertility in men -- why it happens and what is causing it," said professor Karim Nayernia, who spearheaded the research.
"This understanding could help us develop new ways to help couples suffering infertility so they can have a child which is genetically their own," he said.
Nayernia created mice sperm six years ago using similar methods and his team has grown immature human sperm from stem cells taken from bone marrow, The Times (U.K.) reported.
The scientist said his findings would not lead to creating humans "in a dish" but were "a way of investigating why some people are infertile and the reasons behind it."
The findings also indicates that it is impossible to create sperm from female stem cells, meaning lesbian couples cannot have children without a male sperm donor, according to the paper.
Some scientist said the cells needed more testing to confirm their authenticity even though they shared many similar characteristics with real sperm.