© Jellyfish Pictures/Getty Images/Science Photo Library RMThe biobag artifical womb is intended to improve the survival rates of premature babies.

Technology is well on the way to realising ectogenesis, improving premature baby survival and increasing fertility options. But it also has other, more frightening, implications.

We are approaching a biotechnological breakthrough. Ectogenesis, the invention of a complete external womb, could completely change the nature of human reproduction. In April this year, researchers at the Children's Hospital of Philadelphia announced their development of an artificial womb. The "biobag" is intended to improve the survival rates of premature babies and is a significant step forward from conventional incubators. Their results show that lambs (at the equivalent of a premature human foetus of 22-24 weeks) are able to successfully grow in the biobag, with the oldest lamb now more than one year old.

Researchers at Cambridge University, meanwhile, have also kept a human embryo alive outside the body for 13 days using a mix of nutrients that mimic conditions in the womb. The embryo survived several days longer than previously observed and research only stopped because they were approaching the 14-day legal limit for the length of time an embryo can be kept in a lab. In other words, our ethics rather than our technology are now the limiting factor.

The key to survival through ectogenesis is reproducing the conditions of the womb. As scientists become better at that, the gap between the longest time embryos can survive and the earliest time a foetus is viable will narrow. When the two timescales meet, we will have the technology for a complete external womb.

It is exactly this kind of scientific discovery that I imagined for my novel, The Growing Season. In a world that is still similar to present day, the recent invention of an external womb known as the "baby pouch" is changing society. For some, it has brought equality, freedom and choice, while for others the implications are much more frightening. This world is perhaps only decades away from our own; what will happen when our version of the baby pouch arrives?

There will be amazing medical benefits: it could save the lives of premature babies, help infertile couples, give gay and trans people new fertility options and enable older parents to have children. It could offer a safer alternative to traditional pregnancy and childbirth and provide a healthier environment for the foetus by eliminating the risks of drugs or alcohol and providing an ideal balance of nutrients, temperature, movement and sound. But where do we draw the line between ensuring healthy development and only having children deemed to be the "healthiest"? Who decides which type of pregnancy is "best" - women or men? Doctors? Religious leaders? Employers?

There is a danger that whoever pays for the technology behind ectogenesis would have the power to decide how, when and for whose benefit it is used. It could be the state or private insurance companies trying to avoid the unpredictable costs of traditional childbirth. Or, it could become yet another advantage available only to the privileged, with traditional pregnancies becoming associated with poverty, or with a particular class or race. Would babies gestated externally have advantages over those born via the human body? Or, if artificial gestation turns out to be cheaper than ordinary pregnancy, could it become an economic necessity forced on some?

But an external womb could also lead to a new equality in parenthood and consequently change the structure of our working and private lives. Given time, it could dismantle the gender hierarchies within our society. Given more time, it could eliminate the differences between the sexes in our biology. Once parental roles are equal, there will be no excuse for male-dominated boardrooms or political parties, or much of the other blatant inequality we see today.

Women's rights are never more emotive than when it comes to a woman's right to choose. While pregnancy occurs inside a woman's body, women have some control over it, at least. But what happens when a foetus can survive entirely outside the body? How will our legislation stand up when viability begins at conception? There are fundamental questions about what rights we give to embryos outside the body (think of the potential for harvesting "spare parts" from unwanted foetuses). There is also the possibility of pro-life activists welcoming this process as an alternative to abortion - with, in the worst case, women being forced to have their foetuses extracted and gestated outside their bodies.

One thing we can know for sure is that society will be greatly changed by ectogenesis. Growing humans outside women's bodies raises various risks but may at the same time offer hope for new forms of equality and healthcare - and the debate is only just getting started. It is likely that we will have the ability to create an artificial womb within a generation or two. How will we choose to use it?