Please need info,would my stepfather and mother of gained anything from adopting my brother and I for tax purposes back in 1972,would there of been a need to do this ? I have allways been told it was for tax reasons,I believe it was just to get back at my real father.any info appreciated.

No one knows without more info about your stepfather and mother's financial circumstances. Once you were adopted, of course, they could claim exemptions for both of you. I don't understand how they adopted you to "get back" at your birth father. Your birth father had to sign to allow the adoption to take place. This was not done behind his back and he could have stopped it. By allowing you to be adopted he didn't have to pay child support.