COMMERCE, Mich. – Mitt Romney joked about his birth certificate at a rally in his home state Friday, taking a shot at President Barack Obama over doubts about where the president was born.

“No one’s ever asked to see my birth certificate, they know that this is the place that we were born and raised,” Mr. Romney said, as he spoke about he and his wife’s births in the Mitten State.

After decrying the tone of the president’s campaign, Mr. Romney waded into the muck on the stump Friday. Meanwhile his campaign aide assured reporters that the Republican presidential hopeful believes the president was born in the U.S. Mr. Obama, who has released his long-form birth certificate, was born in Hawaii.