Human cloning: could the super-rich do it in secret?

Over decades of covering incredible advances in biology, I’ve seen how certain ideas become fashionable, receive intense media coverage for a few years, and then disappear from public view again. Take human cloning.

After the first cloned mammal, Dolly the Sheep, made headlines in 1997, there was much speculation about whether humans would next be cloned, and even some almost certainly false claims that it had been done. But in recent years there have been virtually no murmurs.

Yet reproductive technologies have advanced enormously since the 1990s. Most notably, the first genetically modified children were created – illegally – just six years after the development of CRISPR. So, I sometimes wonder what’s going on behind the scenes. Could human clones already exist somewhere, out of the blue? Not counting the identical twins, of course.

Why would anyone want to do that? Well, remember how Vladimir Putin and Xi Jinping were caught arguing at a recent meeting about extending life through organ transplants? The best way to achieve this would be to create clones for organ harvesting, so that there are no issues with immune rejection – as has often been explored in science fiction, from the film The island to the book Never let me go.

Then there is the idea that cloning creates a copy of a person and thus can confer a kind of immortality, as shown in the TV series. Foundationwhere an empire is ruled by a succession of clones. But we know from identical twins that having the same genome as someone doesn’t make you the same person. As actress Tatiana Maslany describes it so well in the television series Black Orphaneach clone would be a unique individual. That said, wealthy men can, like everyone else, have irrational beliefs and often seem particularly eager to preserve and prolong their lives.

For scientists, on the other hand, it is the glory of being the first to achieve something. A Chinese commission concluded that the creator of the CRISPR children had “illegally conducted research with the aim of gaining personal fame and gain.”

The objective of therapeutic cloning

So, could there be human clones? For a long time, it was thought that cloning mammals was impossible. Although cells from early embryos can form any part of the body, they specialize quickly and this process was thought to be irreversible.

Dolly proved otherwise. It was created by fusing a cell from the udder of an adult sheep with an egg emptied of its DNA. Dolly became a global celebrity after her existence was announced in February 1997.

His birth gave rise to numerous attempts to create cloned human embryos. The goal was not to create cloned babies, but to obtain embryonic stem cells for new types of medical therapies. Since cloned cells are a perfect match to an individual, they could in theory be used to create replacement tissues or organs that are perfectly matched to that person, meaning they won’t be rejected by the immune system.

But obtaining stem cells from cloned human embryos has proven more difficult than expected. It wasn’t until 2004 that biologist Woo Suk Hwang claimed to have done so. At the time, I was really impressed by the quality of his writing, which addressed every possible objection. Yet the study was fraudulent and the paper was retracted – a lesson I have never forgotten. These days, if an item seems too good to be true, my starting assumption is that it’s not.

Finally, it was not until 2013 that embryonic stem cells were truly obtained from a cloned human embryo. By that time, we had already developed other ways of obtaining matching stem cells, by activating a few key genes, so interest in therapeutic cloning had waned.

Cloned animals and other animals

But in the meantime, animal cloning has become well established. There is sometimes a flurry of headlines when a celebrity reveals they have cloned a pet – most recently, former NFL star Tom Brady reportedly revealed his dog was a clone, created by a company acquired by Colossal Biosciences.

In addition to being proposed as a way to “bring back” beloved pets, cloning is used in agriculture and horse breeding. For example, male horses are often castrated, so if one of them turns out to be a champion show jumper, for example, the only way to use his genome for further breeding is to create clones.

However, animal cloning remains extremely problematic. A 2022 paper on the first 1,000 dog clones created in a lab found that the process is still very inefficient, with only 2% of implanted cloned embryos resulting in a live birth. This is one of the reasons why pet cloning will cost you a whopping $50,000.

Additionally, about a fifth of the cloned dogs had obvious physical differences, including large tongues, oddly colored eyes, cleft palates, and excess muscle mass. Some male dog clones were physically female.

But if a rich or powerful person wasn’t bothered by all this, could they still try to clone themselves?

Why is it so difficult to clone adults

Many sources will tell you that monkeys have been successfully cloned multiple times since 2017, suggesting that it would work with humans as well. What most of these sources fail to say is that, so far, all of these primate clones have been created from fetal, not adult, cells.

The problem is that reprogramming an adult cell to an embryonic state is much more difficult than reprogramming a fetal cell. But to me, cloning means creating a genetically identical copy of an adult – that’s what makes Dolly so remarkable.

Ultimately, I’m pretty convinced that it’s not yet possible to clone an adult human – and in a world with no shortage of dictators and extravagant billionaires, that’s a very good thing.