Sarah Palin's 5th child is really her teenage daughter Bristol's child
Original post made by Anonymous, Ohlone School, on Aug 31, 2008
Bristol Palin left school for an extended period of time, due to mononucleosis according to her family for the last 4-5 months of Trig's pregnancy. Some classmates claimed later that they had seen Bristol Palin pregnant.
Sarah Palin did not reveal to anyone outside her family that she was pregnant until 8 months into her pregnancy. Even then, she showed no signs of pregnancy. Alaskan news outlets commented on this, but did not go further. There are pictures of her at Super Tuesday (just a month before the baby was born).
This could all be clarified with Paternity Testing...