Contrary to common belief, parents do not generally treat their stepchildren less favourably than their own. Until now, many researchers believed in the so-called “Cinderella effect.” It states that it is biologically inevitable that parents care less for stepchildren because they do not spread their genes. Researchers at the Max Planck Institute for Demographic Research (MPIDR) in Rostock, Germany, have discovered an important exception. If there is a reasonable chance of increasing wealth in the parents’ environment then no difference is made between one’s own children and stepchildren. Thus, parental care depends on more than just the biological relationship.