Researchers from Cambridge University have discovered that it is possible to make a baby using skin cells of parents of the same sex.
The researchers have shown, for the first time, that human egg and sperm cells can be made from stem cells of two adults.
Researchers say the technique could mean same-sex couples could have babies in just two years time.
The scientists used stem cell lines from embryos as well as cells from the skin of five different adults.
Ten different donor sources have been used so far and new germ-cell lines have been created from all of them.
The team, from Cambridge, and the Weizmann Institute in Israel, was funded by The Wellcome Trust. They compared the engineered stem cells with human cells from foetuses to make sure they had identical characteristics.
Azim Surani, leader of the project, told The Sunday Times: “We have succeeded in the first and most important step of this process, which is to show we can make these very early human stem cells in a dish. We have also discovered that one of the things that happens in these germ cells is that epigenetic mutations, the cell mistakes that occur with age, are wiped out.”