(名詞) 出生質疑者:質疑美國總統歐巴馬 (Barack Obama) 不是在美國出生 (而是在肯亞出生)、因此沒有資格擔任美國總統的人。這個字通常帶貶義。
birtherism (名詞):出生質疑論。

Last December, in dismissing the birth-certificate argument as a 'canard,' Gilbert wrote, 'The 'birthers' are the new 'truthers.' ' Soon, birther met its counterpart, deather — that is, someone who insists that health care reform will lead to 'death panels' eager to pull the plug on 'granny.'
—Leslie Savan, "On Language: From Simple Noun to Handy Partisan Put-Down," The New York Times, November 18, 2009

Some Republicans have shifted their strategy against the health care bill from fighting over the details to questioning the very constitutionality of mandatory health insurance. And a few have sympathized with the so-called birthers, who continue to challenge Obama's citizenship and legitimacy as president despite all evidence to the contrary.
—Susan Milligan, "Obama domestic agenda largely a one-party effort," The Boston Globe, November 17, 2009