At her London home, Aarathi Prasad is talking calmly about reproduction. But not sex. Her subject is technologies that would take intercourse out of the reproductive equation, advances that could challenge everything we know about family and gender relations.
Like a Virgin: How Science is Redesigning the Rules of Sex, a book by Prasad who holds a PhD in mammalian cell cycle biology from Imperial College London, describes where it could all end up.
The same technologies would enable gay couples to have children created from both their DNA, and make it just as easy for a man to become a single parent as a woman. Prasad writes this would be "the great biological and social equaliser". She believes that the question isn't if it will happen, but when.
Among the most likely technologies is the artificial womb, something she foresees happening within 40 years. If we could grow embryos outside the body, it would change women's life choices entirely. Women wouldn't have to worry about when to have children. Along with eggs created from stem cells, it would be possible at any age. Of all the current reproductive possibilities, it is this potential advance that could be most revolutionary.
The decision to write Like a Virgin grew from Prasad's own desire to have children. She was brought up in Trinidad, then London, and dreamed of having a large family. In her mid-20s, while finishing a PhD in cancer genetics, she had a daughter, Tara. But her relationship with Tara's father ended during the pregnancy. By the time she was 30, her hopes for a big brood were faltering.
"I remember waking up one Saturday morning, thinking, well, if some animals can have babies without males, why can't humans?" Prasad decided to find out more about her choices and what was going on at the cutting edge of reproductive science.
The other possible advance Prasad finds most exciting is the potential to create healthy, new young eggs from our stem cells. There have been studies conducted on animals in which bone marrow from a female has been used to generate eggs. "You can also take bone marrow from men, to generate sperm, and you can generate eggs from men too. It's not magic."
This is because men have an X and a Y chromosome, while women, having two X chromosomes, are more limited in this respect. However, an embryo could still be created that mixed the DNA of two females, a process used in 2004 to create Kaguya, the mouse born without a father. She was created by "constructing an egg out of material from one mature egg, and one immature egg," Prasad writes. Manipulation of DNA essentially allowed the scientists to use an egg's chromosomes as if they had come from a sperm.
This area of technology would allow a woman to procreate alone too, using two of her own eggs, an idea Prasad laughs off. "I wouldn't see a woman creating a baby out of herself. I mean, maybe they would. Maybe Lady Gaga would, some maverick."
But surely for people who want to reproduce and don't have a partner, going it alone might be inspired by confidence in their own DNA and family medical history. "I can see that happening," says Prasad. "I think the real question is, is the baby going to be healthy and the mother able to look after it? If so, then who are we to say?"
Artificial wombs have already been used in reality — for sharks. Scientists in 2008 developed an artificial womb to try to halt the decline of the grey nurse shark. They hope to gestate one from conception.
US and Japanese scientists are finding out whether a similar device could be used for humans. Reproductive researcher Hung-Ching Liu has said having a child in the laboratory is her final goal. Liu has "already managed to grow the lining for a human womb, using a sort of scaffolding over which cells, cultured from a woman's womb, could multiply ... When it was tested using fertilised eggs left over from IVF cycles, the eggs implanted in it, at six days, just as they would in a real womb." Unfortunately, regulations forced Liu to end the experiment eight days after implantation.
Many people find these ideas and technologies enormously problematic. But Prasad points out there was criticism when spectacles were first invented, with some saying the advance went against nature. This was true when IVF technology was first introduced. "I mean, we are machines, after all. We have all these ethical and social over-layers, but the body is a machine."
"There are a lot of things animals do that we can't," she says, "like flying and camouflage, and we've adapted, through technology ... It's funny when people say something is natural, or not. Compared with what? Compared with when? It's this vanity of humans to think of themselves as special, as being at the height of evolution. We're not."
Prasad shrugs. "One of the fertility scientists I was speaking to said that every time there's a press story about eggs and sperm being created, his phone doesn't stop ringing. So there are all these people who are high-falutin', and will talk about the ethics and the morals. And then there are people who are infertile who will just pick up the phone and say, 'Can you help me?'"