So you're thinking about virgin birth...

The Christmas motif has now moved into the realm of the possible.

About 20 years back, I got a call about someone who'd given birth without ever having had sex—and there it was, real life virgin birth. The fact that it was completely doable, given IVF, didn't change my desire to write about it. But I never had the opportunity.

Over the years, other variations on the theme have come up. Here's a quick overview of some of the big ones.  

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Induced pluripotent stem (iPS) cells. In 2006, Japanese researcher Shinya Yamanaka discovered that adult skin cells could be chemically reprogrammed to be similar to embryonic stem cells. The important bit was that the cells were "pluripotent"—that is, capable of turning into any cell type. Three years ago, Spanish scientists used the technique to turn human skin cells into sperm.

In mice, iPS sperm and eggs have given rise to live baby mice. The hope is that someday human same-sex couples will be able to conceive fully genetically related offspring. Alas, it may take awhile: the success rate in mice was only 3 per cent.

Cloning. Like bell bottoms and the mullet, cloning has gone in and out of fashion. Dolly the sheep was first created through cloning in 1996, through a process known as somatic cell nuclear transfer (SCNT)—an egg which had been emptied of DNA was fused with DNA from an adult cell—and the result was that Dolly was essentially a carbon copy of the donor animal.

It felt like cloning-for-all was just around the corner. But in the 20-plus years since, we've learned that some beasts are easier to clone than others, and, alas, humans are among the more technically challenging. (Not to mention more ethically fraught.) Mice, cats, dogs, cows, pigs, and, of course, polo ponies, have all been cloned, but to date, no human has been.

There have been milestones. In 2008, the California company Stemagen announced it had cloned five human embryos using SCNT. In 2013, Shoukhrat Mitalipov, at Oregon Health and Science University, published that his team had used cloning to create human embryonic stem cells

It won't be cheap: the cost of cloning a pet can top $100,000, so we can expect a mini-me to be a lot more. Also, cloning of humans is prohibited in Canada's Assisted Human Reproduction Act with penalties of up to 10 years in prison and $500,000 in fines, and it’s banned in about 15 US states as well. 

Parthenogenesis. This is the poster child of virgin births—there's not even another party involved to tangle with. Literally defined as reproduction without sex, parthenogenesis is when an embryo develops directly from an unfertilized egg cell. It's a perfectly natural reproductive method among some lizards, nematodes, wasps, bees, aphids and others, and on a few occasions, it has been artificially induced in species where it does not happen in the wild. Which raises the question... 

As it happens, in 2007, Elena Revazova, a co-founder of the company International Stem Cell Corporation, reported that she had managed to create early stage human embryos, and then stem cell lines, through parthenogenesis. The company says its interests are in stem cell therapies, however, not alternative forms of reproduction. Indeed, the embryos may not be reproductively viable. 

(In a twist, South Korean scientist Woo Suk Hwang may have actually been the first to do this, some years earlier, although he'd originally claimed, incorrectly, that the cells he'd been working on were the result of successful human cloning.)

In vitro fertilization. If you are a traditionalist, stick with good old-fashioned IVF. Eggs are harvested straight from the ovary, using an ultrasound-guided needle. Sperm can either be self-removed or "aspirated" from the testes with a needle. 

Egg and sperm are then placed together in a petri dish, where, with luck, fertilization occurs. If you don't believe in luck, the doctor can introduce the sperm to the egg, in a technique called intracytoplasmic sperm injection, or ICSI. A few days later, if an embryo looks promising, it can be transported into the uterus via thin plastic tubing and a plunger. Hormonal drugs are required to get the pregnancy properly launched. 

IVF can ring in at a mere 20 grand, and it has a solid success rate of around 35 per cent.  

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Related links

Melissa Hogenboom. "Spectacular real virgin births." BBC Earth, 2014. 

Philip Cohen. "The boy whose blood has no father." New Scientist, 1995. 

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Merry Christmas to all who celebrate.