When did Bette and Kate Kane become relatives?

[thwhtGuardian]

Kate was only in #4 and 5 of the first volume of Batman Incorporated and, in those issues, she doesn't say Kathy is her aunt.

I certainly could be wrong, as it's been a while since I read them but the implication is sill clear as Morrison pretty much brought back all the classic Batwoman adventures into continuity. So if they count, and Bette is Kathy's niece then Kate is also related to Kathy as she is related to Bette.

[Frontier]

Why do I feel like it was mentioned in Morrison's Batman and Robin when Batwoman showed up...

[Oberon]

Kate, may not feel Kathy is her "true aunt" because she didn't know her, in the way that Bette did (she was older, possibly off to the military even) and also wasn't Kathy, the 2nd wife of Bruce's uncle? That could play into it too.

Regardless, and despite messing with the timelines and retcons, Kathy is an aunt by marriage to all of them; Bruce, Bette and Kate. (Kate's sister too).
I still like the easy solution of having Bette, Kate, et all, be Bruce's 2nd cousins ala

Jacob and the unnamed father of Bette were cousins to Martha, but adopted by her parents, and raised as

siblings. So they are adopted siblings

but also first cousins.

And their children would be 2nd cousins to each other.
It's really simple and nearly elegant. Rich folks do things like this all the time (well, you do hear about it).

[Jim Kelly]

It's really simple and nearly elegant. Rich folks do things like this all the time (well, you do hear about it).

I still can't get over the fact that Larry Wolek had sex with his cousin Karen Wolek, who he legally married--and they were both from the wrong side of the tracks in Llanview (ONE LIFE TO LIVE).

[Oberon]

I still can't get over the fact that Larry Wolek had sex with his cousin Karen Wolek, who he legally married--and they were both from the wrong side of the tracks in Llanview (ONE LIFE TO LIVE).

Well, that is the other thing about comics in general (I'm not familar with the plot you mentioned)

comics are like soap operas, for comic fans/ners

The characters all revolve through a set of roles; victim, victimizer and redeemer. In no particular order. Some character's arcs dont' revolve throughe very role or in sequence.