When dogs and cats are neutered, they tend to focus their attention on their human families instead of finding a female in heat. They are generally more attentive and affectionate. Spaying and neutering your pets doesn’t make them fat or lazy. Overfeeding and lack of exercise are what causes obesity, not sterilization. Unneutered pets may mark their territory by spraying strong-smelling urine all around the house. Male dogs may embarrass you by mounting and humping furniture or even human legs. Problems with aggression can be avoided and reduced with early neutering, ideally between 8-10 weeks, or when a weight of 2 pounds is reached.