What causes Stuttering? Could this be a reason?

What causes Stuttering? Could this be a reason? I'm 17. Been stuttering from birth. And it has gotten worse with time. I've know of a lot of stutterers. They are all male. My cousin stutters, a guy in school, a far relative... all below 20 and much better than mine. I've have an identical twin brother and he speaks fine... he's normal. I'm Moses and he said Aaron. My stuttering has no chance of being genetic. My mum took me to a speech therapist when I was a small kid. I dunno how it ended up - it didn't work. My mum told me of a night when I was still I her womb along with my bro. A house breaker was in our room with she woke up in the dark (Dad was abroad). She screamed her wombs off at him. I think I can still remembers that scream in the dark silence. so haunting... just kidding I can't remember a thing! So could that count as a cause??