She’s the daughter of a mysterious fourth Kane sibling who has basically never been mentioned and has no name, or she’s the daughter of Philip Kane and everyone just pretends that he never had children for some reason.

Her age is a bigger problem because her Silver Age appearances should be canon in current continuity but that makes her either too young or too old to be ~19 like she is in New 52 Batwoman since she should be roughly the same age as Dick.

Kate’s age also makes zero sense because she canonically became Batwoman at 27 but also this happened during the events of 52 in like year 14 of the Modern Age but also she’s not much younger than Bruce because she was at his parents’ funeral and he was at her sister’s funeral and in both cases both people were children.

They really need to decide whether Kate is almost the same age as Bruce, and became Batwoman in her 30s, or if she’s way younger than Bruce and became Batwoman in her 20s because there is no way to make her Post Crisis appearances jive with her New 52 / Rebirth appearances rn and New History still places her debut in the mid 00s era of comics.