If you're willing to trust jewish research (i understand, you don't have to), there were about 100.000 of them tested for parent-to-child's autism relations and results look very conclusive.
Here's an article about it:
Are older fathers more likely to have children with autism? A series of epidemiological studies is giving credence to the idea, suggesting that, with age, sperm may accumulate damage that increases risk in the next generation.
www.spectrumnews.org
For fathers (specifically) above 30yo the risk is 1.6 when compared to those below 30, for those above 40 its
6.
That's not to say its the only contributing factor for autism, but that's also not the only risk factor form parental age either.
This:
Higher parental age at childbearing has generated much attention as a potential risk factor for birth disorders; however, previous research findings are mixed. Existing studies have exploited variation in parental age across families, which is problematic because families differ not only in...
link.springer.com
links age of parents to birth defects and infant mortality. Children of 45yo are 1.25 more likely to have physical deformities, they're 2.5 more likely to die before birth.
On one hand that sounds really bad, and those various risks can mount. On the other, the risk for most of those will still be something like 1% as opposed to baseline 0.5%.
The point of no return, as in the age at which various issues start to really escalate is something like 42-45yo.