Scientists have grown an entity that closely resembles an early human embryo, without using sperm, eggs or a womb.

The Weizmann Institute team say their “embryo model”, made using stem cells, looks like a textbook example of a real 14-day-old embryo.

It even released hormones that turned a pregnancy test positive in the lab.

The ambition for embryo models is to provide an ethical way of understanding the earliest moments of our lives.

The first weeks after a sperm fertilises an egg is a period of dramatic change – from a collection of indistinct cells to something that eventually becomes recognisable on a baby scan.

This crucial time is a major source of miscarriage and birth defects but poorly understood.

“It’s a black box and that’s not a cliche – our knowledge is very limited,” Prof Jacob Hanna, from the Weizmann Institute of Science, tells me.

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