For that particular issue you can improve your "gambling" odds by having kids at a younger age, rather than waiting until you've optimized your career and environment.
Anyone who drives risks their life more than they risk having a special needs child at reasonably non-late age.
We just brush off most such gambles because:
1. People have a terrible intuition for probabilities.
2. If it were better, they would go insane.
Also the entirety of society including their families emphasizing the importance of higher education, good careers, etc. even as the latter is harder to achieve and the former becomes increasingly devalued, yet pricy.
Contrast China, for example. 1950-1990 was not a 40-year prosperity party like it was in America and Western Europe. Therefore, they are at least twice as willing as we are to grind, and as a result multiplied their economy an astounding amount over the past 35 years. You can see the same thing in many development countries today. They take nothing for granted.
It should also be noted that the birth rates in China are not increasing, either, despite the end of the One Child Policy. Partly it is also because the younger generation feels immiseration from higher costs of living and fewer opportunities- see the concept of involution.
Finally, during the Great Depression, fertility rates in the U.S. dropped to all-time lows. Not unlike the Great Recession, which has triggered a nonstop decline. We all live in the shadow of 2008.
Education and health care are fantastically expensive now, as well as inflation chipping away at purchasing power, each year more than the last due to compounding effects.
To have children without being financially secure is one of the most foolish, selfish, and irresponsible things anyone can choose to do.