There is a few different potential reasons as well as sexual preference.
Genetic incompatibility - the interspecific cross could only occur one way.
Genetic bottlenecks in the neandertal lineage. A high inbred coefficient could have decreased the neandertal females overall fertility (high deleterious alleles load). This could also cause a rapid reduction in the percentage of neandertal DNA in a mixed population.
Maternal behavior - Neandertals females might not have cared for hybrid offspring appropriately. This could be for anything from milk production requirements to differences in physiological developmental rates.
I think the idea of there being health issues in certain types of mixed families is super interesting because that almost certainly would have been noticed and lead to certain cultural practices or taboos within both species’ societies.
How do we know it wasn’t the other way around?
a paper came out recently. it’s also possible that male humans and female neanderthals made non viable babies.
There is a few different potential reasons as well as sexual preference.
Genetic incompatibility - the interspecific cross could only occur one way.
Genetic bottlenecks in the neandertal lineage. A high inbred coefficient could have decreased the neandertal females overall fertility (high deleterious alleles load). This could also cause a rapid reduction in the percentage of neandertal DNA in a mixed population.
Maternal behavior - Neandertals females might not have cared for hybrid offspring appropriately. This could be for anything from milk production requirements to differences in physiological developmental rates.
I think the idea of there being health issues in certain types of mixed families is super interesting because that almost certainly would have been noticed and lead to certain cultural practices or taboos within both species’ societies.
https://www.smithsonianmag.com/smart-news/neanderthal-men-may-ave-often-hooked-up-with-human-women-thousands-of-years-ago-180988273/