I can't speak towards how YOUR child will react to your baby because each child is very different from the next. I can't even tell you exactly how my niece acted around his baby brother because they hadn't moved hear until the Dominic was 3.
But my neice does have difficulty understanding how to be gentle. She isn't violent or anything, but she can give you a black eye loving on you! How does your son act around pets? My neice picks the cat up by the tails (just wanting to get them so she can hug them) and bites their ears (her version of a kiss.)
- As for your second question?
The latest odds place the odds for the common person to be around 1 out of 150 (less than 1%) But since you have a child with autsim, your odds go up a bit. Maybe 4 or 6 % of you baby being somewhere on the spectrum. But keep in mind, that includes high-functioning, like many think Bill Gates is.
Another factor in figuring odds is the age of the father. If a father is between 30 & 40, his odds are close to double that of a father in his twenties of having a child with autism. If he is over 40, the odds of him having an autistic child are 4 times more likely than when he was in his 20s.
My brother had four kids, two with autism. The autistic daughter was born when he as 36 & the autistc son was born when he was 40.