Half-Human Half-Saiyan speculation. 

It says in the article that half-saiyan's bodies are weaker than full saiyans, but as far as I can tell this is purely speculation. The fact that, during the final battle with Cell, Gohan was stronger than his father at a far younger age, shows that it's simply not true. Goten and Trunks were also both halfbreeds and, since they both acheived super saiyan at a young age, were both stronger then their fathers at the same age. Half-saiyans not being able to acheive Super Saiyan 3 is also pure speculation - since Goten, Gohan and Trunks all stopped training hard at the end of DBZ, logically they wouldn't have gotten there. In any case, Goku was the only case of SSJ3 to ever occur, so it's very fuzzy in the area. The real proof that it's wrong, however, is that Gotenks could go SSJ3. Though you could argue that the two 'saiyan halves' double over, making him pure saiyan, this wouldn't make sense from a genetic point of view. In other words, Gotenks was a half-saiyan and he went SSJ3, so there is no proof to say an unfused halfbreed couldn't achieve it if they became powerful enough. I'm making slight edits to remove those comments.