The 'Breast Milk Baby', being sold to young children, requires the child to wear a provided bib. When the doll's mouth hovers over the sensors that represent a person's nipples, it makes suckling noises.
Costing $89 (£56) each and produced by Berjuan Toys, the doll has attracted criticism including from Fox News's Bill O'Reilly, who said: "I just want the kids to be kids... and this kind of stuff, we don't need this."
A Berjuan Toys spokesman responded: "We've had a lot of support from lots of breastfeeding organisations, lots of mothers, lots of educators.
"There also has been a lot of blowback from people who maybe haven't thought to think about really why the doll is there and what its purpose is.
"Usually they are people that either have problems with breastfeeding in general, or they see it as something sexual."
The Breast Milk Baby has sold poorly in the US, with less than 5,000 sold in the last 12 months.
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