Does the same blood group of couple create problem to the baby?

Hi doctor,

I am 28 years old. I am planning to get married to a girl who is known to me. We have a very good understanding and we love each other. But, we have the same blood group that is B positive. Since blood group is a factor for having babies, do you think having the same positive blood group could create problems for future generation? My brother-in-law told me that if husband and wife have the same blood group, future generation (babies) will have to face problems like a disabled child, died baby born, etc. He told me it could create a problem and he does not want me to marry this girl. So, I am in great trouble right now. How can I give a clear explanation to my parents and my relatives about this issue? My questions are does the same blood group create a problem? If yes, then what basically create problems? And how to overcome this problem I mean the solution to this problem? Are there any precautions that need to be considered for having a baby after getting married to the same blood group?