Spaying and neutering dogs
Your comment made me incandescent with rage. It comes from a 1970's understanding of dog behaviour. Fortunately there has been a lot of research into both the psychology and the physiology of dogs in the past 50 years. My own research into the subject has concentrated on males as I had a male pup. But some points are applicable to dogs of both sexes
1/ Responsible owners of pedigree animals do not allow random mating's to occur
owners of male dogs can tell when they scent a bitch in heat and will put them on a lead. Responsible owners of female dogs don't walk them in public parks etc when they are in heat
2/ Early neutering of males used to be seen as a responsible option. This is no longer the case, dogs should not be neutered until they are fully grown, early neutering will increase the risk of joint issues, hip dysplasia arthritis dues to joint wear and tear etc. in larger breed dogs they are not mature until 2 years old. By this age most dogs will have finished training and so neutering does not bring any benefits
3/ Neutering was believed to reduce the risk of cancer in dogs, this is now shown not to be true, obviously removing the reproductive organs will prevent that cancer but research now shows it will increase the risk of other cancers
4/ Neutering of males was thought to provide a docile dog. In reality juvenile dogs often suffer periods of fear, its a development phase, neutering during that phase will 'fix' the dog in that state
5/ neutering was thought to prevent 'humping' this is a juvenile behaviour which can be trained out. Dogs are either trained to stop hunting or carry on regardless of whether they are neutered or not. Female dogs also hump it is driven as much as dominant behaviour as sexual.
6/ there is a small but real risk that neutering a dog may result in personality changes. I have read heartbreaking stories of males who have changed completely after castration. Anyone who has owned a dog knows they quickly become a valued friend and family member, you love your dog for who He/ she is, you know their personality and quirks, seeing them radically change is akin to losing them.
There are male dogs who become distressed when they scent a bitch in heat and may not be trainable to behave appropriately but these are a small minority of males.