/sci/ - Science & Math

>>16161169
So what's the excuse for Aboriginal Australians or the people of Nepal and Guatemala? They have even lower IQ averages but lack this "less advanced hominid" ghost admixture from Africa.

Also why weren't the Amerindians as advanced as Europeans and East Asians if they were the most ""modern"" derivative of the sapien? I mean it's basically established that outside Mesoamerican Mayan/Aztec civilization Amerindians of both South and North America were effectively Sub-Saharan African tier civilization wise but with worse immune systems and athletic builds.

Is there no way to just test for the presence of sperm in or around the vaginal area? Wouldn't that not be an easier way to go about it?

What was the point of fields like forensic science being involved in sexual assualt cases if not for proof of intercourse? Shouldn't it be extremely easy to prove a woman had intercourse even if you can't prove who it was with?

>>15284884
The masturbation argument doesn't make sense considering the male organ is built for continuous sperm production/ejaculation unlike egg production related to females which is fixed from birth.

I suspect the more likely copurut is the increase wait time for conception. The regions of the world that still have high birthrates are developing countries where men and women have children young compared to developed countries. There might be some epigenetic or prenatal characteristic that modulates future rates of sperm production. Possibly as a biological energy saving costs since the environments of developed countries are less hostile and dangerous. So there's less need to invest energy in that particular area biologically. Maybe there's a reprioritization concerning sperm production in the sexual organ to some other organ instead?

Also I remember reading reasearch somewhere that the level of parasite load in a given environment could alter immunological responses in humans. Thus at least in relation to females depending on the particular parasites involved their reproduction rates would marginally increase. Primarily due to reducing inflammation during conception/ pregnancy. Not sure where the male reproduction fits in the picture related to parasites though.

Outside that all we really have left with is obesity, contraceptives, microplastics or sociological behavior. But I'm not sure if that's right since places like Japan aren't obese (not sure how often contraceptives are taken there). So maybe we are just left microplastics and sociological behavior? Both are definitely more present in developed countries compared to developing countries.