Both Page and Brin turned 40 this year. There's also Brin's heightened risk of Parkinson's. His mother has it, and according to Wikipedia "both he and his mothe

Both Page and Brin turned 40 this year. There's also Brin's heightened risk of Parkinson's. His mother has it, and according to Wikipedia "both he and his mother possess a mutation of the LRRK2 gene (G2019S) that puts the likelihood of his developing Parkinson's in later years between 20 and 80%". He's donated to Parkinson's research in the past, and this investment is certainly along the same lines.