My son, about 3 to 4 at the time, and I were talking/babbling to my 1 y/o daughter. She defiantly still had quite the bit of baby fat on her at the time. I tickled her under the chin and said "Chubby, chubby, chubby". Well it wasn't that long after that when those two kids, my wife and I were all sitting together and my son reaches over to his mother puts his finger under her chin, wiggles it back and forth and says "Chubby, chubby, chubby."
Same son, but the other (younger) sister "Sarah"... My wife just turned 35 when Sarah was born. Fast forward to Sarah's fifth birthday, when my wife just had the big 40 party a few days before. At the 5 y/o's birthday party after the candles are blown out my son got that puzzled look on his face and says "Mom... your EIGHT TIMES Sarah." I laughed so hard but she couldn't be mad because he did his math right.