A US couple have been forced to give up both their children after they were deemed not intelligent enough to care for them.

Amy Fabbrini, 31, and Eric Ziegler, 38, from Oregon, lost custody of their older son Christopher not long after he was born, and then five months ago the state took their second child, Hunter.

Ziegler and Fabbrini were required to take an IQ test after a number of allegations were made against the pair on their parenting style.

A relative to the couple had made a complaint to authorities about Christopher's well-being under the care of the pair, The Oregonian reports.

View photos The parents were forced to give up their children after failing an IQ test. Photo: More

In a child welfare report, it was alleged Ziegler had been "sleeping with the baby on the floor and almost rolled over on him".

Another complaint made by Fabbrini's father, Raymond, said he and his wife were acting as primary caregivers at the time because he felt his daughter didn't have the "instincts to be a mother".

Ziegler scored 66 in the IQ test, Fabbrini 72.

The IQ of the average person ranges from 90 to 110.

View photos The couple were deemed not intelligent enough to parent. Photo: More

Ziegler's test score place him in the mild "intellectual disability" range and Fabbrini's place her in the "extremely low to borderline range of intelligence".

Ziegler had been receiving financial aid through the Social Security and Supplemental Security Income program due to the mental disability he was diagnosed with.

A Change.org petition has since been set up on behalf of the couple by their coach and mentor Sherrene Hagenbach, who says there isn't enough justification to take the children away.

View photos A Change.org petition has over 1500 supporters. Photo: More

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