A poll of 2,000 parents aged 26-41 revealed just 53 per cent can recite all the lyrics to Baa Baa Black Sheep, while only 51 per cent can confidently sing all of Row, Row, Row Your Boat.
Even Humpty Dumpty baffled half of those polled, while Jack and Jill is known by just 43 per cent.
And three in five parents can’t soothe their babies to sleep with a complete rendition of Rock a Bye Baby.
In fact, a tenth of millennial mums and dads do not sing lullabies at all to their little ones – because they have a ‘terrible’ singing voice or feel awkward.
Despite this, 83 per cent think the bedtime routine is a key bonding experienced for parent and baby.
Lisa Parkhill, from baby products manufacturer, MAM, which commissioned the research to debunk myths about soothers, said: “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.
“It’s fascinating to learn just how many rely on the power of their voice to support their baby during these moments – yet many recognise they won’t be releasing a hit single anytime soon.
“But as parents develop these unbreakable bonds with their children, they learn just how important bedtime is to soothe their little one– and even a brilliant chance to unwind themselves.”
The study also found nine in 10 parents will read bedtime stories to their children – and 43 per cent think these have a better impact soothing their little one before bed.
Nearly half of the parents who do read at this time believe It is something they can enjoy together, while many find it a good part of the bonding experience.
And 46 per cent believe it helps to spark their imagination.
The Very Hungry Caterpillar, The Gruffalo and We’re Going on a Bear Hunt were the three most popular bedtime books for millennial parents to read.
Finding the right routine
It also emerged four in five young parents always try to ensure bedtime is a positive and soothing experience for their child, with lowered lighting, warm baths, and giving them a snuggly toy among the top ways to do this.
And one in three of those polled, via OnePoll, will use a soother, while the same amount even use white noise.
Of those who use soothers at bedtime, 87 per cent claimed it helped their child to self soothe and sleep better, while 84 per cent also felt calmer themselves.
Sarah Patel, the founder of Teach to Sleep, said: “There are many ways we can support our babies to fall asleep - such as feeding, rocking and cuddling.
"This all helps to prevent babies becoming overtired and enable them to fall asleep feeling safe and secure, all while laying down the solid foundations for a good night’s sleep.
“Soothers provide sensory input and soothing mechanisms which can be great for calming down, especially during bedtime when babies are often overtired and overstimulated.”
Celebrity parents Harry and Izzy Judd, who have teamed up with MAM explained their bedtime routine.
Harry said: “As with everyone, bedtime with our kids can be a bit chaotic, having a routine definitely helps.
“To help calm everything down, Izzy often takes out her violin to play lullabies or I’ll read the kids one of our favourite books.”
Lullabies young parents can recite the words to
1. Twinkle Twinkle Little Star (55 per cent)
2. Baa Baa Black Sheep (53 per cent)
3. Row, Row, Row Your Boat (51 per cent)
4. Humpty Dumpty (51 per cent)
5. Jack & Jill (43 per cent)
6. Rock a Bye Baby (43 per cent)
7. You Are My Sunshine (38 per cent)
8. Five Little Ducks (37 per cent)
9. Five Little Monkeys (35 per cent)
10. Wind the Bobbin Up (35 per cent)
11. Little Bo Peep (34 per cent)
12. Hush Little Baby (29 per cent)
13. Somewhere Over the Rainbow (29 per cent)
14. Frère Jacques (28 per cent)
15. When You Wish Upon a Star (26 per cent)