Could classic lullabies be going the way of the dinosaur? According to a recent study, we may not be hearing many of them for much longer.

In research commissioned by baby products company Mam, over half of Millennial parents confess that they don’t know the words to many of the classic lullabies. Such standards as Baa Baa Black Sheep (53 percent), Row Row Row Your Boat (51 percent), Humpty Dumpty (50 percent) and Jack and Jill (43 percent) were barely known by parents aged 26-41.

So with lullabies going out the window, what are parents doing to sooth little ones to sleep at night? Well, most millennials say they are reading to their babies. Mam’s research says nine out of 10 millenial parents are still doing that.

“Getting a little one off to sleep is a special, soothing time spent between babies and parents – even if some of the methods might be considered unconventional,” Lisa Parkhill, Managing Editor for Mam said. “It’s fascinating to learn just how many rely on the power of their voice to support their baby during these moments – yet many recognize they won’t be releasing a hit single anytime soon.”

So, what else do parents do when it’s nap time for the little tykes if classic lullabies are gone? One parent admitted rapping a Kanye West tune. Another went with a Rolling Stones tune.

For those that need a refresher or for the first time, check out my list below of 18 popular lullabies that it’s not too late for you to learn.