Pre-baby, a hip lady may know all of the songs playing on the Top 40 countdown. When she enters motherhood, she may start humming a different tune. She may find herself singing "Elmo's World" while in line at the grocery store or bouncing around to "I Like to Move It, Move It" as she finishes up household chores. Cruising moms will find the old classic "The Wheels on the Bus" hard to remove from her memory. Her playlists will quickly be taken over by lyrics that will please her tot — mostly because those little fingers have taken possession of mama's iPhone. Husbands and wives trade late night karaoke sessions at the bar with impromptu duets of "Twinkle, Twinkle Little Star, and "I Love You, You Love Me" in their little one's bedroom. Even if it means knowing all the words to every song in The Little Mermaid instead of Rihanna's latest CD, most mommies wouldn't have it any other way.