"A guard knocked on my door on Tuesday night and told me he wanted to bring my son to the health centre,'' the father said.
"I said, `Why? Not a chance,' but he said, 'Please, we just need to take a sample, and a swab from you and your partner'.''
The father, who moved to Ireland with his extended family from Romania nearly a decade ago, said they had been living in Athlone for five years. He said his son had been born in nearby Ballinasloe.
The toddler was the second child this week to be removed from a Roma family and placed in state care.
The father said neither he nor his family had heard about a seven-year-old girl who was taken from her home in Tallaght, Dublin because they do not watch Irish TV or listen to the news.
The man and his partner stayed with their son while DNA samples were taken from all three at a health centre near their home, but the child was taken away around 10pm on Tuesday.
"He was crying for his mother and we were both so worried, but they told us he would be safe,'' the man said.
"That is all I care about. That he was okay.''
The couple, who have another child, said she was confused and cried for her brother.
"They play together all the time, and my son, he loves to play with his little cars. I just wanted to get him home.''
The parents returned to the same health centre on Wednesday afternoon where they were reunited with their child.
The child's grandparents, who live with the family, said no one should have to experience such an ordeal.
"Imagine someone taking your wallet, or your coat or something like that, you worry about it,'' the grandfather said.
"But for someone to take away a child, it is very bad.''
