C. V. Beechey, D. Green, E. R. Humphries & A. G. Searle. “Cytogenetic effects of plutonium-239 in male mice.” Nature 256, 577 - 578 (14 August 1975); doi:10.1038/256577a0
“Green et al. have recently shown, however, that plutonium reaching the testis after intravenous injection of 239Pu citrate into CBA mice concentrates in the interstitial tissue, outside the seminiferous tubules. They calculated that the average dose rate to spermatogonial stem cells, in which genetic damage can accumulate, was about 2–2.5 times that to the whole testis. In these circumstances, the genetically significant dose is higher than the average tissue dose, which is that normally used for protection purposes.”
Ward Wilson. "The Bomb Didn't Beat Japan - Stalin Did." Foreign Policy National Security. May 29, 2013.
12. Wikipedia: List of Doping Cases in Cycling. Hundreds of incidents listed, from 1880s to 2012.