Current experimental reproductive technology hints at what the future of human reproduction holds

Human reproduction is a complicated process. The miracle of life is, perhaps, that humans have lasted so long when, after a millenia of evolution, our method for making more of us remains relatively unpredictable and arguably imperfect; as many as 25% of pregnancies end in miscarriage, most of them the body’s natural termination of a genetically unviable embryo.

But we live in an age of proliferation of technology that makes up for human shortcomings. What are these advances in the field of human reproduction? What will fertilization, pregnancy and childbirth look like in the future?

It will start with a single cell

In the future, it will start with a single cell. No, not a sperm or egg cell, but a single cell from anywhere on the body – probably a skin cell, since they are so plentiful and most easily harvested. For the last ten years, according to an 18 February examination of the topic in The Economist, scientists have been able to reverse-engineer adult, specialized cells – say, a skin cell, or a cell that makes up liver tissue, which are very different – into stem cells. These are called “induced pluripotent stem cells,” or IPS for short, and they have the potential to turn into any specialized type of cell in the human body.

That technology took a big leap forward earlier this year, when researchers reverse-engineered skin cells from mice into IPS, then caused the IPS to differentiate into differently specialized adults cells — sperm and egg cells, to be precise, in a process called in vitro gametogenesis, or IVG.

While this technology is possible (at least in mice), it is far from being available – so far, it’s only been tried successfully on mice, and there are many, many hurdles to seeing if it works on humans, let alone it becoming standard reproductive practice.

Then we’ll do some Copy + Pasting

So, skin-turned-sperm cell meets skin-turned-egg cell, and they zip together a complete DNA and form an embryo. But – as noted above – the DNA often zips up wrong. Even when it zips up right, it can contain defects that pass from one generation to the next. Some of these inherited defects are benign and may be mild (think, astigmatism) others can be life threatening (a congenital heart defect). This is where a couple of new technologies are making waves.

The first that you’ve probably heard of is the three-parent baby technique. This is used to eliminate mitochondrial diseases, and while the name is very catchy and controversial-sounding, it’s actually pretty mundane (on the spectrum of what’s possible). It takes the DNA of an egg cell with faulty mitochondria, puts it into another egg cell – this one with healthy mitochondria and without its original DNA, and fertilizes the new combo-egg cell with sperm. The first baby was born from this procedure last year and by all reports to date, the child is healthy and thriving.

Mitochondrial mutations are quite rare, and while it’s exciting that women who carry them will soon have the option not to pass them onto their children, the number of people likely to benefit from this technology is relatively small. More will be affected by a technology called CRISPR/Cas-9.

CRISPR/Cas-9 is a gene editing technique that, at its most basic, resembles the Select + Cut + Copy Paste functions on your computer. The bad gene is selected, excised, and a new, healthy gene is copied and pasted in. Last month, researchers successfully used CRISPR/Cas-9 technology to excise a genetic mutation that causes hypertrophic cardiomyopathy from a human embryo (that was later destroyed; it had been created for scientific purposes only).

CRISPR/Cas-9, while promising, is not without flaws. It made news earlier this year for an experiment that, while successful in excising a flawed gene, caused other, fall-out genetic mutations in the process. A study published last month, however, already hints at a solution, paving the way for the next generation of gene editing by increasing efficiency of gene swapping by 50% and halving the amount of unintended fall-out mutations.

CRISPR/Cas-9 is also not without limits. The same study that successfully excised the hypertrophic cardiomyophy-causing gene (inherited from the sperm cell) had trouble inserting a lab-made, healthy version of the gene in its place. Instead, the embryo (or rather, all 112 test embryos) replaced the excised mutation with the healthy gene from the egg. This difficulty means, while it may become possible in the near future to eliminate genetic disease, “designer babies” are still far off; there’s a limit to what kind of genetic manipulation an embryo will stand, said biologist Shoukhrat Mitalipov of Oregon Health and Science University, who led the experiment.

“This is the main finding from our study,” Mitalipov said: Embryos’ natural preference for a parent’s gene “is very strong, and they won’t use anything else.”

So, the skin-turned-sperm-and-egg cells have fertilized, and the resulting embryo edited clean of genetic disease – there’s still a whole nine months to go before a human emerges. What will happen then?

Finally, we’ll incubate – but maybe not inside mom

Last month, researchers from the Women and Infants Research Foundation, of the University of Western Australia, and Tohoku University Hospital in Japan, collaborated to successfully incubate preterm lambs in an artificial womb for one week.

“At its core, our equipment is essentially is a high-tech amniotic fluid bath combined with an artificial placenta. Put those together, and with careful maintenance what you’ve got is an artificial womb,” said Mike Kemp, an associate professor at the University of Western Australia and lead investigator of the Australian team.

While Kemp focused on the potential of a successful artificial womb in furthering the development of extreme human preemies — in itself, a feat not likely in the near future — it’s not difficult to extrapolate the potential to one day an artificial womb incubating a baby for its whole nine months of development, eliminating the physical burden of pregnancy for women altogether.

Such an advancement would also, perhaps, eliminate the physical joy of pregnancy many women experience, and eliminate the embryo-mother communication and interaction, which few scientists deny even if few can explain. All of the advancements discussed above come with implications that could radically change not only reproduction, but the decades of a human life as we know it. After all, the first nine months are just the start. Stay tuned for our next article exploring the ethical and social fall-out of these changes to reproduction.