Could it be?

Could Kate be the rare child who consistently indicates "yes" before "no"?

She's been saying "mmm-hmmm" for months in the affirmative. I tried to write it off as just another babbling noise, but she really does use it correctly most of the time. "Kate, are you my sweet baby?" "mmm-hmmm." "Am I your mommy?" "mmm-hmmm." "Am I your daddy?" *puzzled look*

She still doesn't say no. How strange is that?