Below are a few files where an old issue of medicine gets quite a big support from modern genetics.[hermaphrodites]
The Rambam wrote about this , Jewish tradition [segulot] is brought as well[Rav Kanievsky who was ridiculed for this ][see my letter to that person: fertility issues] and see the conclusion of the journal of genetics [right body side maleness]
JOURNAL OF MEDICAL GENETICS; (1:985;22: 164-70
Throughout the major part of history, theories of sex determination had to be formulated in the absence of knowledge of ova and spermatozoa. The most persistent theory postulated that males are associated with the right parental side and females with the left side.
The Rambam brings in his medical writing already a big hint to this issue [see 2 attachments of the Rambam], the Chinese knew about this polarity, but modern times have put all this wisdom in a geniza [cellar] as with so much old wisdom.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1049419/ the original genetic article [see shortcuts below]