We know of at least two witch-sorcerer children, both female. Is this just coincidence or because their mothers were witches? Are they able to have witch-sorcerer children of both sexes?

Good question! Gender determination comes from the father. Mom always contributes an X (it’s all she’s got) and Dad contributes either X or Y. So it should seem that it would depend on the father, meaning if a sorcerer’s kid is always male, a mix would also be male. Except, obviously, that doesn’t work biologically, because Dad can’t be YY. So what determines that sorcerers always father boys and witches always have girls? Some quirk of biology—either he always contributes Y or she always “blocks” Y…which, yeah, isn’t possible, so the explanation is “magic” biology :)

And if it’s “magic” then I can decide whether hybrids are always female or we just have two examples where it happened that way. My theory is that they’re always female, because if a witch had a hybrid who was a daughter, she could hide the fact she’d been messing around with a sorcerer. If a witch had a son, that would be noticed and there’d be some record of it, which Paige has never found.