PERINATAL EPIDEMIOLOGY Birth defects in children conceived by ICSI compared with children conceived by other IVF-methods; a meta-analysis

have become available for most categories of infertile couples. In 1988, Lanzendorf et al. reported an experiment with intracytoplasmic sperm injection (ICSI) on human oocytes,1 and in 1992, ICSI was presented as a successful method of treatment for certain types of male infertility.2 The ICSI procedure involves the isolation of one particular spermatozoon that is subsequently injected directly into the oocyte with a micropipette. Hardly any experimental knowledge about the ICSI-method was available when the method was first introduced on humans. Several concerns have therefore been raised. Theoretically in the absence of natural selection of the fertilizing Published by Oxford University Press on behalf of the International Epidemiological Association International Journal of Epidemiology 2005;34:696–701 © The Author 2004; all rights reserved. Advance Access publication 23 November 2004 doi:10.1093/ije/dyh363