I've said it before and I'll say it again, please do your own research! I am collecting a wealth of knowledge by reading autism research. I promise, if you stick with it through a few articles, the language will start to make more sense.
If you are intimidated by all the fancy words in academic articles, don't be. Here's some basic vocab that will help you understand what they're talking about. These are the words I ran into the most that I wasn't fully familiar with. I'll keep adding to the list as I encounter words that I learn.
epigenetic- Resulting from external rather than genetic influences.
epidemiology- The branch of medicine that deals with the incidence, distribution, and control of diseases.
etiology- The cause, set of causes, or manner of causation of a disease or condition.
heterogeneous- Diverse in character or content (for our purposes, usually referring to autism as a disorder with many components to its cause)
proband- A person serving as the starting point for the genetic study of a family (for our purposes, a child with autism)
multiplex family- family with more than one child with autism
simplex family- family with one child with autism