Proponents of the technique, which was first tested nearly 20 years ago, regard it as more humane than the conventional methods of controlling wildlife populations, such as shooting, trapping, poisoning or viral diseases. It has drawn support from some politicians and animal-welfare agencies.
An expert in mammal reproduction, Professor Cooper, of the UNSW School of Biological, Earth and Environmental Sciences, questions immuno-contraception on three grounds.
"Firstly, immuno-contraceptives are ineffective against substantial minorities of animals, probably for genetic reasons," Professor Cooper says. "If so, the genes responsible for this lack of response will be passed on to offspring. Within a few generations most of the population will be unresponsive to the immunocontraceptive, so its effectiveness as a form of birth control is likely to be short-lived."
Professor Cooper's research reveals that than in 27 out of 32 immunocontraceptive control trials around the world, 10 per cent of animals remained fertile because they were unresponsive to self-antigens.
His second concern is that the technique is effectively a form of genetic engineering: "Immunocontraception alters the gene pool of the targeted species because those animals who are unresponsive are genetically unusual individuals," he says.
"The job of the immunological system is to combat disease-causing organisms. But there is a danger that the selected minority might be more susceptible to diseases, or that they would be better at carrying disease-causing agents which could affect other animals with which they come in contact.
Source:University of New South Wales