Yes, this similarity between a suffix that eventually came to characterize the feminine gender and the male genitive was present since Proto-Indo-European. Some hypothesize a connection. Similarly, the feminine and the neuter plural in languages that still have the neuter plural usually have the same form, since the neuter plural and the feminine both evolved from a collectivizing suffix (transform a noun for sth. to a group for sth.).
It was always kinda suspicious to me that in Polish (and other Slavic languages I think) feminine nouns end in -a, and genitive of masculine nouns also ends in -a.
Genitive denotes belonging among other things. So, if you have name "Mirosław" the female version is "Mirosława", and accusative for something that belongs to Mirosław is also "Mirosława" (for example "Mirosław's car" is "samochód Mirosława", and "Mirosław's wife" is "żona Mirosława").
It's kinda fucked-up, but it's not something people consciously think about, and at this point I think it's harmless.