The offspring that are produced by sexual reproduction are not genetically identical to their parents. They exhibit variations because they receive chromosomes from two different parents. Since they show variation, they are highly adapted to the changing environment. Asexually produced organisms are genetically identical and all organism show similar adaptations. So, during any calamity, there is a possibility that the whole generation would destroy leading to extinction of species. However, this statement is not true always because of some inborn genetic disorder due to which organism have a risk in their survival, e.g., Haemophilia.