I can relate to something similar - this weekend when we found out we are having a little Girl, M said something along the lines of "girls and their mothers have such a special bond." now, this may or may not be true and is true with sons too - but something in the way she said it (without any bad intentions) made me think...OMG and YOU are her biological mom so of course YOU are going to be the one with this amazing bond and I am going to be on the periphery, what am I, an aunt? a father? etc. Anyway I explained to her how I felt (not that it was rational, really) and she totally understood what I meant, and 100% believes we will both have an amazing bond with our daughter. I know deep inside that will be true - but then I prepared myself for all of the other similar comments that will probably come up when I won't be able to express how they make me feel like I was to her.
I think there are just so many gender-role things ingrained into us from society that we and others say, without considering how they don't apply to everyone, and without any bad intentions. I mean it IS true that you only have one (biological) mom who carried you. But look at children who don't have the chance to know their bio moms and still are so grateful and loving for their adoptive or non-carrying mom - or other parent or guardian. I think my goal in this process is just to realize that most people say these things completely un-maliciously as part of conversation and to just take them in stride and educate them.