Question
asked Her Majesty's Government:Further to the Written Answers by Lord Darzi of Denham on 21 April (WA 233), which field studies support the conclusion, attributed in press reports to a Department of Health spokesperson, that scientifically nothing happens if an animal is inseminated with human sperm; and what the benefits are of mixing human and animal gametes where the resulting embryos are intended to develop beyond the two-cell stage.
Answer
There is no published evidence which suggests that any insemination of an animal with human sperm, whether as part of a scientific study or not, has resulted in a pregnancy. There are biological mechanisms in place that prevent cross-species fertilisation. For a sperm to fertilise an egg there has to be compatibility between proteins present on the sperm and on either the zona pellucida (the shell surrounding the egg) or on the membrane of the egg itself, or both. It is for this reason that the hamster egg fertility test requires the zona to be removed first, before human sperm are added, otherwise the sperm will never penetrate the zona. Humans also have a different number of chromosomes to any other species of animal and are significantly more advanced as a species, making the chances of successful embryonic development low. The Human Fertilisation and Embryology Bill provides for the creation of true hybrids for research to allow scope for potential developments in embryological research techniques which require the use of animal eggs or sperm, thereby future-proofing in this fast-moving field. The Bill provides consistency with the creation of true hybrids being permitted under the 1990 Act for the testing of human sperm fertility or normality using hamster eggs. Any licence application to create a ““true hybrid”” for research will need to prove that its use is necessary. No true hybrid embryo created may be implanted into a woman or an animal, and may not be cultured for more than 14 days or after the appearance of the primitive streak.