"You are unfamiliar with your species?" That gets a headtilt. It's not totally unheard of, though it's definitely odd. With all the aliens in the Mass Effect universe, mixed families and people growing up on planets dominated by species not their own are common, but even then everyone is still usually well aware of their own biology. From the Geth perspective, it's even more odd, since everything was shared between them and Legion is the only unit even capable of functioning as a person when separated from others of their kind.

Unless, of course, her people keep the details of their biology secret even from their own? But that seems counterproductive: what if one is injured and needs treatment? It'd also make reproduction difficult... unless that was the point.