A new device for bioengineering embryo-like structures is shedding fresh light on those earliest, most mysterious – and largely unobservable – moments of human development. Great leaps forward in safe, successful pregnancies and congenital defect prevention await, but so do a host of ethical questions.

I COUNT SIX LITTLE ziggurats side by side, stolid and squat and obviously man-made. They are not going anywhere, but in between them things are on the move. Circles of dots have begun to roil and rotate, angry blimps rising up among the static trapezoids, their contents swirling in a frenzy of disorder. Then, in each one, a ring solidifies and grows in the chaos. It’s fleeting, and the jiggling hoop is soon churned back into the mass as the riot spreads unchecked.

These dots are human cells and their acrobatics are the beginnings of human life, though not as we know it. There is no womb, no pulsing maternal heart. Instead, the cells are born in an elaborate plastic chamber under constant video surveillance, and I am witness to their first two days of existence, compressed into a sparse 18 seconds by the wonders of time-lapse video. The architect of this dazzling piece of cellular music hall is bioengineer Jianping Fu, whose field of expertise – mechanobiology – tries to understand how living cells change in response to physical forces.

Working from his University of Michigan lab on the outskirts of industrial Detroit, Fu is bringing the measured mindset of the machine-builder to the job of constructing life. He is one of an elite cohort of scientists trying to build a replica of the human embryo from the ground up to try to understand just how we are made – and where it can all go horribly wrong.

This area of science aims to alleviate the gamut of reproductive misery, from the anguish of infertility and miscarriage to gathering information about drugs like Thalidomide, which seem innocuous but have grave consequences if taken during pregnancy. Fu’s bundles of cells, dubbed embryoids, could be used to screen drugs for toxicity in the womb. They might also unravel the mystery of why two out of every five pregnancies fail before 20 weeks.

But these scientists, tinkering at the dawn of life, don’t know how far the cells can develop. There is talk their creations could one day provide a source of organs for transplant. The spectre of a baby in a dish looms ominously in the public imagination. Which is why Fu’s bit of kit, written up in Nature in September and described by leading embryologist Ali Brivanlou as “a major advance in the knowledge of early human development”, is also an invitation for humanity to do some circle time on what it means to build a human.

To read my full feature in the March 2020 print issue of Cosmos magazine (Issue 86) follow the subscription links here