The accelerated fragmentation of habitats is probably increasing the frequency of inbreeding in natural populations, raising serious concerns about its influence upon the viability of small and isolated populations. In addition, endangered species are likely to suffer the consequences of inbreeding since they consist of populations that tend to be small and isolated. Under such conditions, matings between close kin become more common, and the offspring suffer increased homozygosity and reduced fitness, a phenomenon known as inbreeding depression.
To avoid inbreeding it is necessary to promote gene flow between populations and to maintain large populations. However, to achieve these objectives involves serious difficulties. The exchange of animals between populations may cause stress, may involve health risks, the translocated animals frequently cannot integrate successfully into the new social groups, and when large bodied animals are involved the costs of transport are high. In addition, to maintain large populations in captive breeding programmes is often impossible given the limited resources available.
Reproductive biotechnologies offer new solutions to facilitate the genetic management of endangered species, such as the development of genetic resource banks which allow the preservation of semen, oocytes, embryos, and other tissues. The main advantage of these banks is that they maintain the genetic diversity of a given species almost indefinitely. Thus, the semen that is cryopreserved may be used for many years after the death of an animal. The existence of a genetic resource bank reduces considerably the number of live individuals which are needed to maintain a viable population, therefore reducing the amount of space needed to breed a species, minimising in this way the costs and increasing the number of species which may benefit from breeding programmes.