>>509486632Same reason than for the post right above you.
Eggs get all spawned roughly 20 weeks into embryogenesis.
A woman's eggs are cells that have been sitting there for her entire life, the chance of something having gone sideway grow exponentially with age.
This include *any* mutation, deficiency, etc be it Down, autism, or having shit taste in neckties.
>isn't it the same for men?Kinda, men have the perk that they generate a fuckton of cells and those need to race - so while the payload can still be fucked from old age, it at least filter out a big bunch of the weakened ones.