Michael Edward Reagan is Adopted
He was born in California to Irene Flaugher (born 1916- died December 26, 1985), a single woman from Kentucky who became pregnant through an affair with an army corporal named John Bourgholtzer (died 1993), and was adopted by Ronald Reagan and Jane Wyman shortly after his birth.
In 1938, Reagan co-starred in the film Brother Rat with actress Jane Wyman (1917–2007). They were engaged at the Chicago Theatre, and married on January 26, 1940, at the Wee Kirk o' the Heather church in Glendale, California. Together they had two children, Maureen (1941–2001) and Christine (born June 26, 1947; died June 27, 1947), and adopted a third, Michael (born 1945). Following arguments about Reagan's political ambitions, Wyman filed for divorce in 1948, citing a distraction due to her husband's Screen Actors Guild union duties; the divorce was finalized in 1949 making him the only U.S. president to have been divorced.