Sex ratio- ESS

Fisher stated that sex ratio of 50:50 is an ESS, because if one looks at it, it holds a strong truth. The 50:50 sex ratio can be for the most part proven, because if you think about it no matter how the initial birth ration is cut it is still going to go back to the 50:50 sex ratio. Lets say for example more males then females were born this year that would mean that females had a bigger advantage when it came to finding a mate and that some of the males were not going to be able to mate, and die off. Even if you look at it the other way around in which there were more females than males then some of the female would go unmated and end up dying off, and this would still drive the sex ratio back to 50:50. Autosomes would favor this because autosomes are only carry half of the genes and when two of different sexes combine then it makes up the diploid. On the other hand sex chromosomes would not favor this because they want to be favored over the other. Sex chromosomes think that the next generation should only be made up of their genes.