by David Adams
The Guardian (UK)
19 may 2005
Scientists are developing artificial wombs, sperm and eggs - but
will this lead to reproduction in a dish?
Readers of a squeamish disposition, look away now. The following
article has vivid descriptions of stomach-churning experiments,
freakish deformity and sex. Lots of sex, often done very badly.
really might be better off trying
This is all a self-fulfilling event
because we trash our health and the health of all living organisms.
And yet we are shocked at the degradation and marketing of life in
It may be straight out of Brave New World but there's nothing very
brave about it. In fact it is being propelled by ignorance, fear and
Reproductive technology would be an unprofitable business without a
market to sustain it. That market is the result of the destruction
of human fertility by chemicals, radiation and fast-paced
lifestyles. Therein lies the ignorance, fear and greed.
Infertility is indiscriminate. So too is pollution.
Some sectors of society get more because of their work or home
location, but all people, regardless of economic status, are getting
enough to destroy their fertility and that of coming generations.
"Human babies grown in a laboratory," a front-page story in a
British newspaper screamed earlier this month. The story, of course,
was wrong. It was unfertilized human egg cells that had been
produced - but could the overexcited headline be a sign of things to
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
Further, some warn we may one day be able to incubate such fetuses
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
"I have no doubt there are people
fantasizing about creating a baby
with no humans involved," says Thomas Murray, president of the
Hastings Centre, a bioethics think-tank in Garrison, New York.
"I am sure there are people intrigued by that prospect, though I'm
not one of them. It is never too early to start thinking about the
moral implications. It's amazing how quickly things develop and stun
Those in doubt should pay a visit to the
laboratory of Hung-Ching
Liu, an embryologist at Cornell University in New York.
In 2002, Liu stunned the world of reproductive medicine by claiming
to have recreated a woman's womb, using uterine cells grown on a
biodegradable scaffold bathed in a broth of hormones and nutrients.
When Liu placed fertilized human embryos created during IVF
treatment inside, they nestled into the wall of the womb and began
to attach themselves to the endometrial cells that make up the
lining - just as in the early stages of pregnancy. Liu stopped the
experiments after a week because regulations prevent human embryos
being developed much further.
No such restrictions apply to animals and, in unpublished work, Liu
says she has now grown mouse fetuses 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
Just as with the human embryos, the tiny bundles of mouse cells
nestled into the artificial womb lining and began to attach
themselves. Liu watched as blood vessels formed, then miniature
placentas and, eventually, the amniotic sac - an embryo's personal
Liu, of Cornell's centre for reproductive medicine and infertility,
"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 fetuses 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 fetuses were abnormal, so she pulled
"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
"What other factors it needs to develop into a normal baby is still
unknown. We're only getting something that we think is close to the
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 fetuses 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
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.
Embryos being made from synthetic eggs and sperm, however, is a
different story. The artificial eggs that prompted the errant
newspaper's headline were prepared by a team led by Antonin Bukovsky
at the University of Tennessee Graduate School of Medicine in
Knoxville. Bukovsky says his technique could provide a potentially
limitless supply of eggs - a scarce resource in fertility treatment
and stem cell research.
His claims have yet to be tested, and scientists have questioned why
such groundbreaking results appeared in the little-known journal Reproductive Biology and Endocrinology, edited by Bukovsky. 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 Josephine
Johnston, also at the Hastings Centre. "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."
Like Liu, Eppig has been experimenting with mice, and his results
also tell a cautionary tale.
In 1996, Eppig succeeded in growing mouse eggs in his laboratory. He
started with ovaries from newborn animals, cultured them and
dissected out precursors of eggs, called oocytes, and associated
cells. After careful nurturing, many of the resulting eggs began to
grow when fertilized, but the 190 early-stage embryos transferred
into female mice produced just one live pup. Eggbert, the first
mouse born from a lab-cultured egg, was far from normal. He suffered
from obesity and neurological problems.
Since then, Eppig's team has worked to improve the culture medium
used to grow the eggs, and in 2002 it reported the birth of 59
apparently healthy mice. Others are working to produce synthetic
sperm and eggs from less obvious sources: the ubiquitous stem cells.
In 2003, Hans Schoeler and Karin Huebner at the University of
Pennsylvania's School of Veterinary Medicine, said they had produced
eggs from stem cells extracted from mouse embryos. Others, notably
Toshiaki Noce at the Mitsubishi Kagaku Institute of Life Sciences in
Tokyo, have tried to repeat the trick with sperm, though it is
proving more difficult.
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
Contrary to some reports, the same is not true for
"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
"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. You can imagine all levels of
bizarre scenarios but I think we need to stay focused on fundamental
questions of medical importance."
Besides, he says, sperm and eggs generated from stem cells in a
laboratory will probably not develop properly.
"There are lots of
reasons to think they are restricted or abnormal in some way and may
not be able to support full development. This is a long, long way
from reproduction in a dish."
"Ethicists do need to be thinking about this and they
do need to be thinking about it now. But actual applications are
really not on the immediate horizon."
Were significant advances to be made along the road of artificial
reproduction and gestation, the issues would clearly be significant.
"The issue with artificial wombs might not be so much in taking a
fetus to term, but using them to save very premature babies," says
Richard Ashcroft, a medical ethicist at Imperial College, London.
hospitals could use such wombs to keep babies alive that would
otherwise be too premature to survive, it could well have
implications for abortion law, he adds.
But as with all technological advances, new techniques are not
guaranteed a market. How many couples would want to see their baby
grow in an artificial womb unless there was no alternative? And as
Ashcroft adds, for the vast majority of women, the importance of
going through the birth process cannot be overstated.
Artificial sperm and eggs arguably raise more profound issues.
Knowing that genetic material came not from living humans but from
synthetic gametes grown in a lab would reinforce the distinction
between parents as genetic donors and those who raise the child.
For now, the sheer difficulty of perfecting the techniques necessary
for fully artificial reproduction means the ethical issues are
little more than talking points, says Eppig.
All of these things are very, very hard to do. They are interesting
mind games to discuss over a couple of beers after work. While we're
going to learn a lot about development from these studies, making
embryos for animals and people is a long, long way off.
Don't hold your breath