Babies could be born ‘without biological mothers’

Babies could be born without a biological mother after scientists created functional human eggs from skin. American researchers demonstrated it was possible to replace the DNA from an egg with the genetic material from another person’s skin, and turn it into a sex cell ready for fertilisation. When the team fertilised the egg with sperm, it began growing into an embryo, until the experiment was halted at six days – the point at which an embryo would be transferred to the womb in IVF.

The breakthrough opens the possibility of skin DNA from a man being placed inside a donor egg and fertilised by another man, leading to a baby with two biological fathers and no DNA from a woman. It could also provide an unlimited supply of fresh eggs for women who struggle to conceive because of age, infertility or medical treatment. Dr Paula Amato, a professor in obstetrics and gynaecology at Oregon Health and Science University, told The Telegraph: “In theory, the technique could result in a limitless number of eggs.

“The skin cell DNA however can come from anyone, even if they personally don’t have any eggs or remaining eggs – older women, women after cancer treatment, people born without eggs, men... So, it’s a way to produce eggs genetically identical to the person providing the skin cell, even if they personally don’t have any eggs, and allows them to reproduce to have a genetically-related child. “A same-sex male couple could potentially have a child genetically related to both partners.”

Egg and sperm cells are different to other cells in the body because their DNA is wrapped up in just 23 chromosomes, half the usual number. When eggs and sperm fuse together, theycreate a “full set” generating an individual with unique DNA.

All body cells contain a nucleus, which houses the characteristics of a person, and since the 1990s, scientists have been able to transfer that nucleus into a donor egg to create clones. But cloning is considered unethical in humans, and does not produce a unique individual.

The new process is called “mitomeiosis” and starts with the same process as cloning – transferring the nucleus from a skin cell to a donor egg – but then coaxes the egg into giving up 23 of its chromosomes. The technique produces a viable egg that can combine with the 23 chromosomes from sperm, mimicking the natural process of fertilisation. The resulting embryo could then be implanted in a mother or surrogate.

The team has produced 82 functional eggs, which were fertilised in the lab, although only 9 per cent went on to develop into early embryos, known as blastocysts, and all suffered from chromosomal abnormalities.“ Some of the embryos developed to the blastocyst stage, five to six days after fertilisation, but all had an abnormal complement of chromosomes, too many or too few or not one from each pair,” added Dr Amato. “Thus, these would not be expected to develop further into a normal baby.”

The team are now going back to the lab to try and tweak the chromosome pairing and segregation process, so that the correct chromosomes are given up by the egg. British scientists said the breakthrough was “impressive” and potentially transformative for people who could not have genetic children.

Prof Ying Cheong, Professor Of Reproductive Medicine and Honorary Consultant In Reproductive Medicine and Surgery at the University of Southampton, said: “This breakthrough is an exciting proof of concept. In practice, clinicians are seeing more and more people who cannot use their own eggs, often because of age or medical conditions.

“While this is still very early laboratory work, in the future it could transform how we understand infertility and miscarriage, and perhaps one day open the door to creating egg or sperm-like cells for those who have no other options.”Prof Richard Anderson, deputy director of the MRC Centre for Reproductive Health at the University of Edinburgh, said: “Many women are unable to have a family because they have lost their eggs, which can occur for a range of reasons including after cancer treatment.“The ability to generate new eggs would be a major advance... There will be very important safety concerns but this study is a step towards helping many women have their own genetic children.”

However other experts warned that there were ethical and regulatory hurdles to overcome if the technique was ever to be used. Roger Sturmey, professor of reproductive medicine at the University of Hull, said: ‘The science is impressive, and the researchers were careful to seek the necessary review and guidance for their work. “At the same time, such research reinforces the importance of continued open dialogue with the public about new advances in reproductive research. “Breakthroughs such as this impress upon us the need for robust governance, to ensure accountability and build public trust.” The research was published in the journal Nature.