So that you understand a thing or so about autism.
From the CDC:
studies have shown that among identical twins, if one child has ASD, then the other will be affected about 36-95% of the time. In non-identical twins, if one child has ASD, then the other is affected about 0-31% of the time. [1-4]
Parents who have a child with ASD have a 2%–18% chance of having a second child who is also affected.[5,6]
ASD tends to occur more often in people who have certain genetic or chromosomal conditions. About 10% of children with autism are also identified as having Down syndrome, fragile X syndrome, tuberous sclerosis, or other genetic and chromosomal disorders.[7-10]
Almost half (44%) of children identified with ASD has average to above average intellectual ability. [Read article]
Children born to older parents are at a higher risk for having ASD.
A small percentage of children who are born prematurely or with low birth weight are at greater risk for having ASD.
ASD commonly co-occurs with other developmental, psychiatric, neurologic, chromosomal, and genetic diagnoses. The co-occurrence of one or more non-ASD developmental diagnoses is 83%. The co-occurrence of one or more psychiatric diagnoses is 10%.