The North West England MEP added that families should be encouraged to have no more than one child in an effort to combat climate change.
But he said he did not support "Chinese-like ideas of compulsion".
"What's the single most effective thing couples can do to play a part in combating global warming? It is to have no more than one child," the Mirror quoted him, as saying.
Davies added that he wants his plan to be considered by the EU.
However, not all are convinced with Davies' theory.
Labour MP Sion Simon said: "This is a crazy idea."