Over tea at her home, Aarathi Prasad is talking about reproduction. But not sex. Specifically not sex.
Her subject is technologies that would take intercourse out of the reproductive equation. Their potential is summed up in the final paragraphs of her new book, Like a Virgin: How Science is Redesigning the Rules of Sex.
Here she describes the "ultimate solo parent" of the future. This woman can use her own stem cells and an artificial Y chromosome to produce healthy new eggs and sperm at any age, is capable of reproducing entirely alone by making one of her eggs behave like a pseudo-sperm that can be used to fertilise herself, and has no need to carry the embryo in her own body.
Instead it gestates in an artificial womb, which acts as a highly evolved incubator.
The same field of technology 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 that this would be "the great biological and social equaliser" before adding that the question isn't if it will happen, but when.
She is softly spoken and thoughtful, and our conversation circles around chromosomes, DNA and IVF, before returning repeatedly to the artificial womb.
If we could grow embryos outside the body, it would change women's life choices entirely. We wouldn't have to worry about when to have children -- between this advance and eggs created from stem cells, it would be possible at any age.
Men and women could have an equal role in parenting, right from conception. 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, with her parents and brother, 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 on a bed with my daughter thinking: 'well, if some animals can have babies without males, why can't humans?'"
She decided to find out more about her choices and what was going on at the cutting edge of reproductive science. Her book takes a broad look at the notion of reproduction without sex, beginning with ancient stories of the virgin birth.
But the book is most extraordinary when it considers the future of reproduction without sex.
Along with the artificial womb, 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, she says, 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," she adds.
The child wouldn't be a clone, she notes, because, "every time you create an egg there's a shuffling of the DNA, which is why siblings don't tend to look the same."
But surely for people who want to reproduce and don't have a partner, going it alone might not be prompted by narcissism -- more by their confidence in their own DNA and family medical history, versus that of an unknown donor?
"I can see that happening," says Prasad.
Artificial wombs would challenge social attitudes too, perhaps even more profoundly.
Prasad writes about the team of scientists who, in 2008, developed an artificial womb to try to halt the decline of the grey nurse shark.
In addressing this problem, scientists have gestated wobbegong embryos (wobbegongs are similar to grey nurses, but not endangered), for increasingly long periods in an artificial womb, with great success. They hope, soon, to gestate one from conception.
Scientists in Japan and the US are working to find out whether a similar device could be used for humans.
There are regulatory and ethical as well as technological barriers to overcome in many of these reproductive advances, but when I ask Prasad whether she thinks we'll see artificial wombs used by humans in her lifetime, she is positive.
"If my lifetime was another 40 years, yes," she says.
If babies are gestated outside the human body, it would immediately disrupt all our notions about who should be the primary parent, and about male and female roles as a whole.
"It would get away from that question of mother and father," says Prasad, "and instead become: what is a parent?"
In Like a Virgin, Prasad describes some of the ethical dilemmas that might result, exploring, for instance, the bond between a pregnant woman and her baby.
This is often considered sacred and essential, but she sees it differently. Watching a child grow from a tiny cluster of cells, right through to birth, might result in a bond that was equally special, she suggests.
Researching the book, Prasad visited a neonatal unit in Hackney, east London, where she saw very premature babies in incubators. The experience felt voyeuristic, she says, because "you're looking into this womb, this box. It's so beautiful to see this doll-like creature growing."
She compares this with the scans pregnant women have -- that moment they're first able to 'see' their child.
"There's this beautiful, perfectly formed child [on the screen] and you're in tears. That's bonding.
"Feeling the baby inside you can be too, but sometimes it's really hard for the mother ... This whole concept of the perfection of maternal bonding -- it's not like that. There's no ideal."
In fact, she says, it could be good because it would be impossible to get pregnant like this accidentally "and, secondly, the womb can be a bad place for babies." She mentions smoking, drinking and drug use, and adds: "This whole idea of nature being fantastic -- it's not.
"We can learn from it, but we can also improve on it."
That's true in some cases, but what about positive influences in the womb, the influence a healthy, happy mother has on a growing foetus?
Prasad believes it would be possible to replicate these too. "If a baby was growing in a box from beginning until end, and you knew what those influences are, you could manipulate them.
The signals that make a person happy are because of certain chemicals they're producing in their brain, dictated by their genes, dictated maybe by one of their parents being like that. But it's a chemical signal, and those are completely replicable in an artificial situation.
"I mean, we are machines, after all. We have all these ethical and social over-layers, but the body is a machine."
Continuing in this vein, Prasad says a "hardcore, serious mother" whose child was gestating in an artificial womb could be injected "with stuff to make her produce milk by the time the baby is born, so she is expressing certain hormones that we know are related to maternal bonding.
"You could recreate all that."
Given that men and women would have an equal chance to bond with the baby during gestation, there would be more potential than ever for parenting to be fully shared. So does all this spell the end of sex? Are we about to start reproducing in entirely new ways?
Prasad says she doesn't think these technologies will be used by everyone.
"The people who are interested in it are those who have problems in having babies".
But it's not hard to imagine artificial wombs being used more broadly. If there was a viable, entirely healthy alternative, would women choose to go through pregnancy?
Prasad recognises that many people find these ideas and technologies enormously problematic, but takes a scientist's view. She points out that there was criticism when spectacles were first invented, with some saying the advance went against nature.
"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?"
There has been uproar over reproductive technologies before, she notes.
"With the first IVF there was an outcry, and then people say: 'Well, if it helps people who are childless . . .'"
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?'"
Like a Virgin: How Science is Redesigning the Rules of Sex is published by Oneworld