Responses
it's probably a genetic birthmark
yeeeaa.... sounds more logical instead of not showing the mother's full face (〜￣△￣)〜
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They show both because he loved both the mom and Tae (well he thought he did) so it was to show that eventually he would fall for kotou because he's fallen for both the mom and sister already.
So i've read this more than 4 times and I still don't quite understand Torou's family. So the mom is a AV actress, so why did they show Tae-chan next to her in the final chapters?? Do all the children have that mole on the their chin as a birthmark??