Sesame Beginnings is aimed at children under two

Sesame Beginnings features characters such a Baby Big Bird and Baby Elmo.

The Sesame Workshop said it worked closely with child development experts to produce the series.

But the Campaign for a Commercial-Free Childhood (CCFC) says experts have found no evidence that watching TV under the age of two has any benefits.

The CCFC says the American Academy of Pediatrics, which represents children's doctors in the US, has previously said young children should not be put in front of the TV.

"There is no evidence that screen media is beneficial for babies and growing evidence it may be harmful," it said.

These are the absolute antithesis of park-your-baby-in-front-of-the-TV kind of videos Dr Kyle Pruett, Zero to Three

"Sesame Beginnings will encourage babies' devotion to TV characters that have been licensed to promote hundreds of other products."

'Adult information'

The Sesame Workshop said it had worked closely with advocacy group Zero to Three in the making of the DVDs.

"We didn't go into this in an impulsive way," said Rosemarie Truglio, Sesame Workshop's vice president of education and research.

"We wanted to invite the parent into the viewing situation, to give the adult information about child development."

Dr Kyle Pruett, of Yale University and a member of Zero to Three, said that although he was sceptical at first he believed it was better to provide options for parents who wanted to allow their children to watch TV.

"These are the absolute antithesis of park-your-baby-in-front-of-the-TV kind of videos," he said.

"They are thoughtful, informative - it's not a corporate campaign trying to draw kids into TV life."