Did Obama's father forget when he was born?

Did Obama's father forget when he was born?: "With the release of Barack Obama Sr.'s immigration file, it is now clear that he began misstating his year of birth at some point during his stay in the United States.

Born June 18, 1934, the senior Obama began listing the year of his birth as June 18, 1936, on U.S. Immigration and Naturalization Service forms two years after arriving in the U.S.

The long-form birth certificate released by the White House lists his age as 25, corresponding to a 1936 year of birth.

The nurses or clerks who prepared the Obama long-form birth certificate apparently took enough care to establish that Obama's father was born in 'Kenya, East Africa,' not simply in 'Kenya,' and they listed his race as 'African,' not 'Negro.'

Why would they get the age wrong? If the document were forged, why would the forgers not list an age corresponding to a birthdate of June 18, 1934?"