I use bio-guy here more than cis-guy simply because it sounds when it makes a word, and even those that are going to argue where "biology" starts, in the head or the crotch or the chromosomes, are still going to know exactly what I mean. But it only gets used in places where there's a specific need to classify people based on precisely what they were born with between their legs...which is only places where gender is being discussed. Everywhere else, it's just "guys", I tend not to use any specific terminology, "Well, ok, you were born with one, I had to buy mine" to an open minded friend and such...