The illegitimate son of a 25-year-old notary, Ser Piero, and a peasant girl, Caterina, Leonardo was born on April 15, 1452, in Vinci, Italy, just outside Florence. His father took custody of the little fellow shortly after his birth, while his mother married someone else and moved to a neighboring town. They kept on having kids, although not with each other, and they eventually supplied him with a total of 17 half sisters and brothers...
http://www.mos.org/leonardo/bio.html