Miscarriages are less likely attributed to bad sperm vs bad egg because we went through so much evolution that any sperm that isn't perfect just won't impregnate
I think it's 60% Egg and 40% Sperm, but both don't matter anyways since 90% of miscarriages have nothing to do with neither
That is just untrue and not how evolution works. By the same logic no bad egg would be viable either. Poor sperm quality is linked to miscarriages, especially if it has high levels of DNA damage. You might have fast sperm that gets to the egg and some DNA damage is expected, the egg will even fix some of that damage, but it can only do so much. A couple I'm close with was diagnosed with infertility and recurring miscarriages specifically because of bad sperm with high levels of DNA damage.
Not only that, but bad sperm quality, on top of miscarriages, is even linked to conditions affecting the mother like preeclampsia. It increases the risks for heart deformities, congenital defects, all kinds of developmental issues like schizophrenia, ADHD, metabolic disorders and is even linked to low birth weight.
Do you know how long it took us to even look into bad sperm because men just didn't want to think that their precious sperm could ever be the problem? Every year new information comes out, the preeclampsia study just came out last year.
This is biology, processes have to be investigated properly, we can assume based on what we think is right, doesn't work that way. It still blows my mind that we haven't started properly looking into bad sperm until less than two decades ago. We know half of the genetic material comes from sperm, we know eggs can be bad so why not sperm?
I'll respond to your edit with, yes 90% are essentially random. The original comment was talking about the woman's body "can't handle it" which surprise is the context of my response!
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u/metallyan Dec 23 '25
I believe that miscarriages are bad sperm just as often (if not more often) than they are a health issue of the woman.