Auma Obama, 2007.   (Photo: AP)

Obama: It’s Complicated
Owing mostly to his father, who had children by four women, Obama has seven living half-siblings (one he had never met died in 1984). He’s tight with two of them. The first is Maya Soetoro-Ng, his younger half-sister, the child of Obama’s mother and Lolo Soetoro, her Indonesian second husband. Maya stayed with Obama’s mother after she divorced Lolo, and she took time off from teaching high school in Honolulu to make appearances at her brother’s campaign stops. The second, Auma Obama, is Obama’s older half-sister, the child of Barack Sr. and his first wife in Kenya. Obama and Auma first met when Auma visited America after their father died in an auto accident in 1982. “I knew at that moment, somehow, that I loved her … Even now I can’t explain it; I only know that the love was true, and still is, and I’m grateful for it,” Obama wrote in Dreams From My Father. Four of Obama's other siblings — Abon’go Malik Obama, George Obama, Auma Obama, and Mark Ndesandjo — have written books about the family, some of which take issue with the depiction of Barack Obama Sr. by Barack Jr. and biographers such as David Remnick.

Romney: Youngest of Four
At 64, Romney is no spring chicken, but he's also no doddering grandpa. (See: Favorite Hobby.) But the same might not be said for his siblings: George Scott, his brother, is six years older than him; Jane LaFount, his sister, is nine years older; and Margo Lynn, the eldest of George and Lenore's four children, is 12 years older. As a boy growing up, the age difference meant Romney was the true baby of the family, garnering special attention from their father. At least one of the other Romney kids tried following their father and mother into politics — George Scott made a serious bid for the Michigan attorney general's office but failed, instead winning a seat on the board of trustees for Michigan State University. (He was a regional co-chair for McCain's campaign in 2008, but it looks like it was with brother Mitt's blessing — the two appeared at the opening of McCain's Great Lakes headquarters together.) George Scott's ex-wife, Ronna Stern, also tried her hand as a Michigan politician, a two-time (failed) senatorial candidate. But there was some bad blood there, so much so that Romney Senior even endorsed her 1994 primary opponent. Ronna’s sister, however — who lives in Bloomfield Hills, where Romney grew up — is married to Romney's 2008 campaign national chairman.