Over-populated free roaming species can pose a large problem for society. Certain methods of population control include surgical castration, however a great number of societies have recently imposed restrictions on this form of sterilizing, due to ethical reasons and animal welfare legislations. There is a possibility of many complications, including bleeding, infection, and risks of anesthesia. So, other forms of sterilization have been imposed, known as chemosterilants. Two types of chemosterilants are commonly used: