For right owner a Doberman is a good dog, but presents a real challenge for those unsuited to own it.
The Doberman was created to be a defence dog to protect human life not attack (chase/bite/hold) and while a strong watch dog/territorial instinct if part of its genetic makeup, a sound dog will not wake up one morning and bite someone, but would snack on a wild rabbit caught on the run or the family pet bunny if the opportunity arose.
Dogs born with unsound temperaments, soft and nervous are both faults, are more likely to be produced by puppy farms and back yard breeders, than top show/sport and working kennels that are few and far between.
In a nutshell, the Doberman is standoffish with strangers and will take notice of them but not react, accepting their presence in the same way they would a table or tree, there but uninteresting.
If children are taught not to jump on the dog, pull it around, rough play and leave it be when the dog walks away or sleeping, and to treat kindly and with respect, and the dog and kids are supervised, a sound dog will be fine with children.
What can happen is when a baby comes alone the dog’s routine is changed for the worse, with less exercise and mental stimulation, with significantly reduced time spent on and enjoying the company of the dog. Pregnancy and birth is one of the reasons a nice tempered dog is turned over to rescue.
It is a breed characteristic for Dobermans (male) to begin to develop same sex aggression from puberty –typically six months, but this is not a hard and fast rule as all dogs are individuals within a breed – and contrary to the opinion of some, it cannot be surgically removed by castration or trained out of the dog.
While there are a few Dobermans born with a low level strength of this trait that is not something an owner should expect or count on. Two male dogs in a household when one is a Doberman may seem fine for the first few months, but when the young dog begins to mature and its breed begin to develop at puberty, the relationship between two males changes, with escalating aggression and dog fights the norm.
Some people natural show the leadership qualities a determined, pushy, independently minded, highly intelligent, intractable and wilful breed like the Doberman needs to see from day one. Leaders are controlled, calm, quiet, fair, consistent and assertive in everything they do with the puppy, train the puppy in obedience and good manners and provide it with boundaries, structure and routine which dogs love.
By nature the Doberman is an active working breed that is up on its toes eager to be outside doing something with its mind and working off its considerable energy – has tremendous stamina as an adult, combined with speed and agility – and needs and love to learn. Training is ongoing throughout a dog’s life.
You could suggest that your mother researchs the breed thoroughly, its history and purpose, drives, temperament and characteristics which will shape the way an adult thinks and behave and spends time with well bred adult dogs, and then make an informed decision based on what you have learned if this is a breed she could meet the needs of and be confident having it in the home.
On the other hand if your mother definitely does not want the breed, it would be respectful to accept her decision and continue to have an input when you and your family research different breeds.