Well first of all, there is a genetic difference between the two races, just nothing that conventional xrays can detect. Otherwise Baltar's cylon detection device would not work. Besides there aren't too many humans who can throw people around with one arm and can transfer their consciousness to another human when they die.Originally Posted by MASON
Second of all, at this piont we only know that cylons can "conceive" with humans, but not necessarily breed with them since Sharon is only pregnant and has not successfully given birth yet. It's possible that the cylons have already gotten to this point in the reproductive process - conception but not successful births. Six mentioned something about "love" being the missing element. It is possible that the creator of the cylons programmed the cylons in such a way that would allow them to reproduce only if certain parameters are met?