The Guardian

Scientists are developing artificial wombs, sperm and eggs — but will this lead to reproduction

in a dish?

London: “Human babies grown in a laboratory,” a front-page story in a certain newspaper screamed earlier this month. The story, of course, was wrong. It was unfertilised human egg cells that had been produced - but could the overexcited headline be a sign of things to come? In their efforts to tackle inherited diseases and help infertile couples, scientists across the world are developing techniques and technology that ape the most basic - and morally complicated - of biological functions: human reproduction. Taken together, the work poses some troubling questions. In the most recent research, the scientists claim to have grown eggs using stem cells scraped from anonymous human tissue. Others are trying to do the same with sperm. How long before they succeed? And could the two be combined to produce a synthetic embryo? No serious scientist advocates such a move, but, as the parallel field of human cloning demonstrates, not everyone in a white coat is a serious scientist. Further, some warn we may one day be able to incubate such foetuses outside the body, as described so memorably in Aldous Huxley’s dystopian classic, ‘Brave New World’. Work to develop such “artificial wombs” is already under way. So is artificial reproduction on the horizon?

Those in doubt should pay a visit to the laboratory of Hung-Ching Liu, an embryologist at Cornell University in New York. Liu says she has now grown mouse foetuses in her artificial womb for 17 of their 21-day terms. This is equivalent to about 31 weeks in humans, at which point babies have been viable for more than a month and can routinely be nurtured to normal development if born prematurely.

Liu says: “Normally people don’t grow mouse embryos beyond 10 days. This goes way beyond that and forms a mouse shape housed inside a little bubble. It was wonderful. We were really amazed.” But, peering inside, Liu could see that something had gone wrong. “The foetuses were not healthy. We could see the mouse inside but it was severely deformed.” Liu repeated the experiment more than 150 times. Not all the embryos developed, but for those that did, the story was the same. By 17 days it was clear that the foetuses were abnormal, so she pulled them out. “They were like a stillborn baby, just sitting there, doing nothing. I don’t think they were alive.” When Liu cut them free from their amniotic sacs, the mice were dead. She thinks that the problem lies in the animals’ blood vessels, which do not form properly and so fail to circulate the required nutrients. Others are working at the other end of gestation, with equally startling results. A team at Temple University in Philadelphia, led by Thomas Shaffer, has developed breathable fluids that allow sheep delivered at half term to survive outside their mothers. And scientists in the laboratory of the late Yoshinori Kuwabara in Tokyo have used tanks of synthetic amniotic fluid to incubate late-stage goat foetuses taken from pregnant animals for several weeks.

Some have speculated that the two ends of this research will eventually converge - allowing a two-cell embryo to develop into a living, breathing baby, entirely under laboratory lights. Scott Gelfand, director of the Ethics Centre at Oklahoma State University in Tulsa, was so concerned that he gathered experts together in 2002 for a conference titled ‘The end of natural motherhood: The artificial womb and designer babies’. Murray, who attended the conference, says that while discussing the issue is easy, making it a reality is very, very difficult. “I think it is crucial for us to work out where to invest our moral anxiety and I think that artificial wombs are not there yet. They are much more complicated than people think and not a neat lab trick like squeezing out the nucleus from a cell and putting a new one in its place.” Although the ever-dependable Raelian cult say they have developed a version called a Babytron to incubate their clones, no reliable scientist believes that we are anywhere close to a working artificial womb capable of replacing a woman. But it is clear in which direction research in the field is headed.

“It is not ridiculous to say this moves us towards the point where we can do completely artificial reproduction,” says scientist Josephine Johnston, speaking on embryos being made from synthetic eggs and sperm. “But if you want a healthy baby, there are lots of easier ways and things people would rather do. It’s a bit like the whole debate in IVF and how we could design babies, but the fact is that most people don’t want to use IVF. They do it because they are desperate.” As John Eppig, a developmental biologist at the Jackson laboratory in Bar Harbor, Maine, puts it: “I’m sure bioethicists are already thinking about this, but even if the ability to do it comes along, I don’t think it is going to replace the current method used to make babies in most homes.” Synthetic eggs and sperm made from stem cells raise new ethical questions, mostly over parenthood. Schoeler and Huebner’s results suggest that eggs can be made even from male cells - potentially allowing a gay male couple to produce children through sexual reproduction. Contrary to some reports, the same is not true for lesbian couples.

“To make a sperm you need a Y chromosome,” explains George Daley, a stem cell biologist at the Children’s Hospital in Boston. “There’s been all kind of speculation about whether you could make sperm from female cells. You can’t.” Daley adds his voice to the chorus insisting no reputable scientist is involved in this research because they think it could be used for reproduction. “There are other issues that are more valuable to study, such as the development of the germ lineage, which has enormous implications for biology, fertility, the development of diseases and congenital defects. I think we still need to stay focused on fundamental questions of medical importance.”