Should parents have the right to discard embryoes if they show signs of genetic defects like cleft palates or Down's Syndrome? The German parliament says - yes - under some circumstances. The Bundestag has just voted to allow in some cases the use of pre-implantation genetic diagnostics, or PGD. The procedure, also known as embryo screening, has been controversial in Germany, partly as a result of the way disabled people were treated by the Nazis.