The child (not pictured here) has been placed with youth services
Authorities in Bavaria, southern Germany, have taken a seven-month-old boy into care after his parents offered him for sale on eBay "as a joke".
The unnamed child was advertised as a "nearly-new baby" with a starting price of one euro (£0.80, $1.6).
Police have launched an investigation into possible child-trafficking by the infant's father, 24, and mother, 23.
The mother told a German newspaper: "It was only a joke. I just wanted to see if someone would make an offer."
Speaking to Bild, she said she was also being made to undergo psychiatric tests.
'Gotten too loud'
A police spokesperson in the Bavarian town of Krumbach said the mother had also told police the offer had been a "joke".
"That's not yet clear," the spokesperson added.
"Detectives are investigating on suspicion of child-trafficking."
Police were alerted by a number of internet users across Germany who had seen the offer in the auction website.
According to the police, the posting read:
"Offering my nearly new baby for sale, as it has gotten too loud. It is a male baby, nearly 28in (70cm) long and can be used either in a baby carrier or a stroller."
No offers were made for the child in the two hours the advert was showing, police said.
EBay deleted it but assisted police in tracking down the parents, the Associated Press adds.
A couple from Vancouver, British Columbia, Canada has been arrested on charges of public mischief after listing their seven day old baby girl on the popular Internet classified ads website Craigslist.

The listing claimed that the baby was unexpected, "healthy and very cute". It asked CAN 10 000 for the baby. It also listed a phone number belonging to a stolen cellphone, which was used to find the couple.

It was first noticed by a 62-year old grandmother browsing the website for furniture, who said "I was shaking, and I thought, 'Come on, how did this even get through?'" The couple claimed that the listing, which has since been removed, was a hoax.

The father, Jeremy Pete, had a history of car thefts and evasion of police, while the mother, 23-year-old Bethany Granholm, had convictions of property theft, fraud and impersonation. The parents have now been released, but charges are still being considered. The baby has been placed in provincial care.

A suspected copycat incident occurred just four days later, also offering a seven-day-old baby girl for CAN 10 000 on Craigslist. This incident turned out to be a hoax, and no child was in danger.

Last week saw a similar incident in Germany, where a couple listed a seven month old baby on eBay. In this case the police have launched a child trafficking investigation, despite the parents' assertion that the listing was a joke.