The Bactra Review   The Origins of Life
Actually, that's not quite true. As the selfish-gene perspective leads us to expect, there are some genes (segregation distorters, for example), which monkey with the reproductive machinery so that they are disproportionately likely to be found in gametes, and so, ceteris paribus, tend to spread through the population. It is thought that they do not become totally fixed in the population because, in effect, every other gene has an interest in stopping this, and so the evolution of modifying effects is favored, reducing and even eliminating the bias in favor of the outlaws.