On Smooth Peas and Healthy Babies

In the mid-nineteenth century, a monk named Gregor Johann Mendel carried out a set of experiments in the garden of the abbey in Brno, Moravia (present day Slovakia), and, by doing so, planted the seeds of modern genetic science. At the time, it was known that crossbreeding of plants, and of animals, could give rise to new traits, but the nature of these traits, and the way in which traits were transferred from one generation to the next, was completely mysterious.