Rush Limbaugh on Thursday lashed out at feminists -- who he called "feminazis" -- over the news that male genitalia are shrinking.

The conservative radio host pointed to an Italian study which found that the average male penis was 10 percent smaller than 50 years ago. Researchers cited weight gain around the waist, smoking, stress and environmental pollutants as factors.

But Limbaugh wasn't buying that explanation.

"I think it's feminism," he declared. "If it's tied to the last 50 years -- the average size of [a male's] member is 10 percent smaller than 50 years -- it has to be the feminazis, the chickification and everything else."

"Give 'em time and they'll blame Bush. But air pollution vs. feminazis? Ha!"

In 2009, Limbaugh worried that the Center for Disease Control was considering a proposal to encourage circumcision for all baby boys.

"If we need to save our penises from anybody, it's Obama," he said at the time.

In other possibly unrelated penis news, IO9 reported on Thursday that doctors have been recently struggling with how to treat Koro Syndrome, which is the irrational "fear that the genitals are shrinking, or retracting into the body, and that when they finally do disappear, you will die."

Listen to this audio from The Rush Limbaugh Show via Media Matters, broadcast Sept. 20, 2012.

NOW READ: The Simpsons lampoons GOP-backed voter ID laws