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(view spoiler)[I'm confused by the excerpt. Lucien is a son but his mother is happy he was born a girl. Lucien seems to be depicted as male but with a uterus. Only hair, eye color and height are provided. Is he physically female but identifies as male? Are his “external parts” male with female bits inside? I don’t think I can invest myself in this book anymore if I’m left feeling this confused the whole time. (hide spoiler)]
Nora He's a "girl" (and a Lady) because he has a uterus and can give birth, but he is a son because he has boy parts. Just like his sisters (all but one who is what we think of as the conventional girl), who are daughters but are probably thought of as boys, because their girl parts extend and are used to impregnate. They are daughters, but they are called Lords. Just like any sons born who do the impregnating, who would be what we think of conventionally as a boy. So boys do the impregnating and the inserting and "girls" carry the babies. But "son" or "daughter" (also "he/she") refers to the genitals.