The structures differ from real human embryos in many ways, and cannot develop into them because they lack several embryonic tissues, as well as the supporting yolk sac and placenta needed for further development.

The human stem cells used to derive hematoids can be created from any cell in the body. This means the approach also holds great potential for personalised medicine in the future, by allowing the production of blood that is fully compatible with a patient’s own body.

There is no shortage of taboos in modern society, only the concrete focus shifts as generations change. Some things lose their sacredness and others gain it.

It was probably completely safe to draw a Muhammad cartoon and sign it in the West of 1950. Doing this now is a recipe for spending the rest of your life under police protection.

The explosion of hate speech laws all over the West is another instance thereof, though much less sanguinary.