Logan was born with a congenital heart condition called Tetralogy of Fallot. He is considered a "pink tet"...meaning that his coloring is pink instead of blue. Here is a little info about his condition...you can click the link below to find out more.
Taken from the American Heart Association website:
Tetralogy of Fallot refers to a combination of abnormalities with four key features: 1) A ventricular septal defect (a hole between the ventricles) and 2) obstruction of blood flow from the right ventricle to the lungs (pulmonary stenosis) are the most important. Sometimes the pulmonary valve isn’t just narrowed but is completely obstructed (pulmonary atresia). Also, 3) the aorta (major artery from the heart to the body) lies directly over the ventricular septal defect and 4) the right ventricle develops hypertrophy (thickened muscle).
Because of the pulmonary stenosis, blood can’t get to the lungs easily, so the blood doesn’t get as much oxygen as it should. Because the aorta overrides the ventricular septal defect, blood from both ventricles (oxygen-rich and oxygen-poor) is pumped into the body. People with unrepaired tetralogy of Fallot are often blue (cyanotic) because of the oxygen-poor blood that’s pumped to the body.