I took away my step brothers ability to start a family.
When we were teenagers, my mother remarried and in return I had a new step-brother. He was a older than me, and often vented his frustration on me verbally and sometimes physically.
I told our parents, but nobody did anything. I started asking my friends for help, and one day in school while he was picking on me my best friend then walked up to him and kneed him in the groin. He spent fifteen minutes rolling around on the ground, and left me alone for a week.
From then on, I would kick or knee him in the testicles whenever he tried to abuse me. It was very effective, and as I did it more often I started doing it harder and harder and this one time when I caught him stealing my money I hit him there so hard that he threw up and locked himself in the room for the whole day.
One day, he got so fed up with no longer having any power over me that he fought me physically. He called me a b**** and pinned me against the wall by the throat, but he got so full of himself that he got distracted monologuing that I freed myself from his choke and bit his hand to make him let go and kneed him in the b**** with all the strength I could muster.
I did it harder than I ever did before, and he started hunching over and fell to his knees. I don't know what came over me, but I ran up to him and kicked him in his sexual organs until he closed his legs and curled up into a ball, I was so flustered I missed most of them but he took at least three direct hits.
I kicked his back a few more times before running into my room, and when they got home he was still there.
I was sent away to live with an aunt, while I eventually found out they took him to the hospital.
We recently reconnected, and I found out he was married for several years. He still has no children despite being in his late thirties, and I often wonder if it had anything to do with me.