Genetic susceptibility. Most of the epidemiological studies are pointing at an interaction of genetics and environment.
There is no getting around the data on age. A mother over 40 has a 77% higher risk of having a child with autism than does a mother under 25.
If age was irrelevant, that risk differential would not exist or would be so small as to be irrelevant. Maternal age has no effect on color blindness or hemophilia, but infant gender does because they are x-linked recessive disorders.
So some women are genetically inclined to wait till 40 to have babies?
“There is no getting around the data on age. A mother over 40 has a 77% higher risk of having a child with autism than does a mother under 25.
If age was irrelevant, that risk differential would not exist or would be so small as to be irrelevant. Maternal age has no effect on color blindness or hemophilia, but infant gender does because they are x-linked recessive disorders.”
Back to my original question. If the studies point to an interaction of genetics and environment, what genetics are different in 40yr olds that haven’t had prior pregnancies compared to those that have? Because it looks like the entirety of that difference is the exposures between age 25 and age 40. Ie, the environment. The older you are, the more ‘exposed’ you are. Else there would also be age differences in strictly genetically heritable diseases as well.