“uncomfortable truth ” — as if converts were a shameful scandal????
There were many conversions in ancient times (i.e. before the rise of Christianity and Islam, which made conversion to Judaism a capital offense). And for obvious reasons, there were always more female than male converts (for men, conversion meant a radical loss of status, whereas most women did not have much in terms of rights to begin with, not to mention the complications of Bris Milah for an adult male). Remember also that for most the last 2000 years a Geir needed to come u p with a fake yichus (to avoid being executed), and it is easier to pass off woman than a man (since Jewish males had more contact with the goyim than the women did). One should note that most “Sefardim” were living in areas where the non-Jews were closely related to the Jews (Middle East) so from a genetic perspective, converts would be indistinguishable from Jews.
I suspect that the lighter skin color and frequent blond hair among Ashkenazim is more the result of “natural selection” (Jews who could pass for goyim were more likely to survive pogroms). Remember also that many people for northern Europe ended up in the Middle East (e.g Viking mercenaries hired by the (Byzantine) Romans, Legionaries recruited in Northern Europe and assigned to the Middle East, not to mention slaves who in Roman times were likely to be Celts, Germans or Slavs), with their genes mixing with everyone else’s.