In most situations a pet available for adoption will either already be spayed/neutered from the shelter or it will be a requirement for adoption. This requirement to spay/neuter is to reduce the number of pets and hopefully reduce the number of pets flowing through shelters and wandering homeless. If the pet “supply” is limited, the thought is that people will take better care of their pets and of course there will be fewer pets abandoned to shelters. This is especially true with cats, where too many unwanted litters cause more kittens than can be adopted.
Neutering/Spaying your pet is good for their health. It reduces the chances for infection of the uterus and it reduces breast cancer in females. In males it reduces testicular cancer and certainly the urge to roam due to females in heat. As a consequence, less roaming reduces injuries from fighting other males or being hit by a car. Neutered males are less aggressive and may also have a decrease in territory marking, or lifting of the leg to urinate leaving their smell.
Neutered pets are better for you, as household companions. They are less likely to develop certain health hazards, are less likely to have aggression, territory and roaming issues and do not have the frustration of heat cycles. Please do not add to the pet overpopulation problem, neuter your adopted pet.