Leading fertility doctor, Simon Fishel, states the case for pre-implantation genetic diagnosis and saviour siblings

use of PGD in order to help families with a sick child have a tissue-matched sibling. He argues that the good brought about by the birth of a tissue-matched sibling far outweighs any perceived harm.
For more details see Stating the Case for PGD

Science Media Centre produce guide to Embryonic stem cells and human admixed embryos

The Science Media centre have produced two guides explaining the science behaind parts of the Bill. The two guides, one on the four types of human admixed embryos and one on embryonic stem cells, provide a celar and understandable explanation of the science.
The guides can be downloaded here: ES Cells & Human Admixed Embryos