Simplify the following text for a Grade 5 native English-speaking person.
Original: The Mamas & the Papas ( credited as The Mama 's and the Papa 's on the debut album cover and sometimes shortened to Mamas and Papas ) were a Canadian\/American vocal group of the 1960s ( Denny Doherty was from Canada ) .
Simplified: The Mamas & The Papas were a popular pop music singing group in the 1960s .