Answer: Reproductive problems from imbalanced hormones can occur when abnormal levels of estrogen and androgen sex hormones develop, and can cause infertility and other health issues.
Based on the scenario being described within the question it can be said that two or more populations of toads will form that are genetically distinct from each other because the toads will eventually become isolated on each island. This is mainly due to one population beating out the other in each island and/or adapting the the unique features of the island.
