try surviving without a kneecap, ACL, and MCL. that's what every city guard in skyrim has to. makes survival hard- and kneecaps aren't vital organs.
just because there's magic involved doesn't mean the fundamentals of biology and physiology are any different (save for maybe the argonians).
and yes there are ways to prove it! vampires are considered undead. needless to say, being pregnant while not technically "alive" in at least some ways is a bit awkward for the fetus- unless they're like Blade, now that event (9 months pregnant mother gets turned) is a realistic possibility of someone literally being born from a vampire mother i could get behind.
as shown by skyrim, the human souls of vampires are in oblivion (presumably coldharbour because molag bal and stuff).
Vampires are unable to age and are immune to disease; and while not impervious to death, a vampire may be killed only by meeting a violent end.
you know what other TES beings have that same kind of conditional immortality (albeit a much better version)? Daedra- supernatural beings who cannot have children.
now while vampires aren't strictly daedra, they share some similarities- especially as vampires are indirectly connected to molag bal, the progenitor of the vampire. given their daedric roots, it's not too far of a stretch to say that traces of the daedra (a word that itself is a translation of "not our ancestors") are present in all vampires.
additionally, even the best ideas in video games generally draw inspiriation from real life- see the mythology behind the Dhampir: the human/vampire hybrid originating from Balkan folklore.
https://en.wikipedia.org/wiki/Dhampir. short story: vampiric men have
just as much a LOT more of a sex drive as normal living men.