If aliens were to examine a human, they would think we were just slavish organisms designed to feed microbes and carry them around. Our bodies contain ten times more bacteria than cells , and there are an estimated 3.

Between 30 and 40 million people in Europe suffer from rare diseases —many of them children. As most of these diseases have genetic origins, gene therapy is a major hope for their future cure .

Peanut, egg and soy are more common food known to trigger an allergic reaction, a problem affecting around 8% of children in the EU. Intuitively, you might not list apples as causing allergic reactions.