Study design: A cohort study. Study population: 5- and 8 year old children born after PGD in The Netherlands for various indications and their parents. Control groups consist of 5 and 8-year old naturally conceived (NC) children of parents who have considered PGD treatment and 5 and 8-year old children born after in vitro fertilisation/intracytoplasmatic sperm injection (IVF/ICSI), and the parents of the two latter groups of children.