Outdoorsy, my oldest toyed with the phrase "real mom" for about a month. We have always been open with them about where they came from. They know they were conceived with the help of a donor and they know their birth stories, but they have forgotten from time to time who gave birth to them. Sometimes they thought their mama gave birth to one, but they can't remember who. When O was 6 or 7 he said something about me being his "real mom." I told him that his mama did all the same things for him that every mom does for their children, with the exception of giving birth. He didn't have the language to explain that he was using the phrase "real mom" to imply biology, but that was what it came down to. Not a difference in love for her.
Before that, when he was 5ish, I asked how he felt about not having a dad. He said, "I do have a dad. You." That cracked me up, and I think it had something to do with his perception of masculinity and femininity, but watching them go through the standard phases where they identify more with the mom, then the dad, then the parent of their own gender, he clearly adores his mama, but identifies more with me. I'm not butch in the slightest and he has many men in he life, but it has been interesting to watch him grow.
Little sister is much less expressive of these things and now very clear on some things but unclear on others. She is very into skirts, like her mama, has short hair like her mama, has certain food preferences like her mama. At our house, she is taken with Sara. She wants to do everything that Sara does, except chew with her mouth closed. I see how we divide along gender lines All The Time, if I was a boy. It's often Sara and A and the boys and me.
This went way off track, I think my kids have this perception that I'm not a woman, even tho I identify as one. They question the mom thing, possibly because I'm not like the other moms they know. Our families are all so different, it's harder to draw parallels but the kids don't seem to struggle because it's all they know. I mean, it's not like they can't have more than one sister/brother/grandma/cousin, why not more than one mom?