my dog HELP!!!

Question
hi thanks very much in getting back to me
my girl springer is 2 yrs old and my son is 16 , its  only in certain situations this has happened it seem that when my girl dog wants a stroke of my son my boy dog doesnt like it ,and starts to growl at him , it is manly my son thats getting the growls noone else. i also have 2 daughters and an husband and his ok with everyone else thanks pam x
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The text above is a follow-up to ...

-----Question-----
hello
my dog is 3 yrs old a springer i have just brought a girl dog same breed i have had her for 2 weeks now and my dog is turning nasty showing his teeth and growling to my son i dont know what to do please help thanks pam
-----Answer-----
So you had the 3 year old Springer Spaniel, then brought home a female Springer Spaniel (you didn't say how old she was), and now your 3 year old male is showing aggression to your son? How old is your son, and does the dog behave like this all the time, or only in certain situations? Please get back to me as soon as possible, and in the meantime keep your son and the dog separated.

Answer
OK. That clears up things a bit better for me. The problem is that the male Springer does not respect your son or view him as being one of the 'alphas' (leaders, in charge) of the 'pack' (your family). I would recommend having your son do LOTS and LOTS of obedience with the male dog (if the dog doesn't know any, enroll him in an obedience class and have your son take him), put your son in charge of feeding the dog and walking him, and immediately start doing "Nothing in Life is Free (NILIF)" with the dog - that goes for everyone in the household. If the dog growls at your son, or otherwise shows aggression towards him, you or your husband should correct him with a strong, verbal "NO," followed by a collar correction if necessary.

I would highly recommend enlisting the help of a professional dog trainer who has experience with aggression, to come and help you work through this problem. Giving advice like this over the internet without having seen the dog in person can be difficult. I think your best option is getting a trainer in your area involved.

Good luck,
Kristen