 Prenatal testing is often presented, in medical practice and in some bioethical literature, as protecting the well-being of children. It is often argued that it is wrong to bring a child with a disability into the world if we can prevent doing so (i.e. Savulescu 2001 and 2007, Davis 2001). However, this claim faces the much discussed “nonidentity problem”, which was introduced by Derek Parfit (1976, 1984) and adapted to the reproductive ethics context by many authors (e.g., Steinbock 2009, Wasserman 2005, Brock 1996) (see the entry on “The Nonidentity Problem”). In short, the problem is that you cannot harm a non-existent person by bringing it into existence, unless the person's life is so dreadful that nonexistence is preferable. That life with a disability or chronic illness is predictably worse than non-existence is not plausible for most of the defects for which we test—notably including Down syndrome, which is the most common target for testing and abortion. Some philosophers take an antinatalist stance and argue that human life in general is prima facie worse than non-existence (e.g., Benatar 2006), but it is a far more widely held stance that bringing a child into existence does not typically count as harming that child.