If my boyfriend's sister has Aspergers Syndrome does that mean our children are likely to get it too

I know this sounds terrible but it is something that worries me. My boyfriends sister has AS and I am worried that increases the likelihood that potential children we have together will have it too. His sister is 29 and still has to live at home with their parents. I really want kids but to be perfectly frank I want healthy normal children someday and if it is likely to be inherited I might think twice