Doing without sex
Pregnancy and childbirth are major challenges to the female body. An expectant mother has to provide nutrition and a safe environment for her growing baby, and childbirth thrusts a vulnerable baby into a harsh outside world. Until recently, death of mother or infant during or immediately after birth was common in the West (and remains so in many parts of the developing world).
Small wonder, then, that much science fiction includes visions of pregnancy outside the human body. In Aldous Huxley's 'Brave New World', for example, babies are grown in special incubators and reproduction is entirely divorced from sex. This has the advantage that the authorities can control what type of child is produced, from the 'alpha' elite to the 'deltas' and 'epsilons' who do manual work.
In vitro fertilisation
The first step in producing a new individual, fertilisation, can take place outside the body. In 1978, Louise Brown became the world's first 'test-tube baby'. Sperm and egg are fused in culture; the embryo develops a short while and is then implanted into the mother's womb.
This procedure, in vitro fertilisation (IVF), has become routine, and around two million children have been born by IVF.
It is used when would-be parents have difficulty conceiving a child. For example, an egg may not travel through a woman's reproductive system properly or a man may have a low sperm count. If a man has immotile sperm, which cannot swim to an egg, a sperm nucleus can be directly injected into the egg (a procedure known as intracytoplasmic sperm injection, ICSI).
Although common, in vitro fertilisation still has a relatively low success rate (typically about 20 per cent) and is not a pleasant experience. It is far from a 'lifestyle' option but a last chance for couples having difficulties conceiving.
The artificial womb
Creating an embryo may be relatively easy but nurturing it to the point of independent existence certainly is not. The arrival of artificial wombs has made headlines periodically over the past decade, but they remain science fiction at the moment.
The medical need arises from the desire to save developing fetuses that might otherwise die – for example if an expectant mother's womb is damaged in a road traffic accident. A second important area is the survival of premature babies. Great strides have been made in this area, and infants born so prematurely that they would have died in previous eras can often be saved. But there is a limit and even those that do survive often suffer brain damage or other harm.
The growth of a new baby in the womb is highly complex, and the placenta plays a key role in providing the right nutrients, protecting the fetus from harmful substances and removing waste products. Recreating these functions artificially is a huge challenge.
One approach is to try to grow womb-like structures in culture. A group at Cornell University in the USA has had some success in growing cells from the lining of a human uterus and is using tissue engineering to mould them into a womb shape.They have also grown mouse embryos nearly to term in an artificial womb (though the newborn mice did not survive).
In separate experiments, a Japanese team has used 'uterine tanks' to support the development of goat fetuses. They took early stage embryos from pregnant goats and brought them to full term (though again the newborn animals did not survive).
Medical need and social application
This kind of work inevitably seems to lead people to imagine 'baby factories' growing new infants to order. In 'Brave New World', the State was the bad guy, seeking central control, but now the fears are more about individuals creating 'super-babies' or babies becoming commodities chosen to order like a new car.
But it is worth remembering that the primary purpose of this research is to save babies' lives or to help the infertile. There may one day be a possibility for wider application of these technologies, but for the foreseeable future these are likely to be difficult procedures to carry out and used only when absolutely necessary.
Take preimplantation genetic diagnosis (PGD). This involves taking a cell from an early human embryo during IVF and carrying out genetic tests on it. Through this technique, parents at risk of having a boy with an X-linked genetic disease can have a female embryo implanted. Or in families with inherited disorders, an embryo without a disease gene can be implanted.
There are fears that this could be used to create 'designer babies', where parents select embryos with particular features. In reality, the links between genes and particular features (intelligence, say) are so complicated that this is unlikely to be a realistic scenario. Then the procedures themselves are difficult and not undertaken lightly. Finally, in the UK at least, reproductive technologies are highly regulated (by the Human Fertilisation and Embryology Authority), so socially undesirable applications would face many hurdles.