Remember that (mitochondria and Y-chromosomes aside) it's not the case that sons inherit their genes from their fathers and daughters from their mothers. The children of an upper-class father and a lower-class mother will have half of their genes from each parent regardless of sex or class.
Being upper class and lower class apparently doesn't have significant biological indicator to affect strategies such as these.
The poorest among our society are still mostly drawing in the same amount of calories, and feel happiness and sadness, age mostly in the same way.
There are no indications that billionaires are significantly happier/healthier than us - in fact these indicators are mostly tangential with wealth past a certain point.
maybe post-Industrialization, but a whole lotta people died of famine and disease before then, and the ones getting hit hard were the poorest.
For example, imagine just for argument that the probability of the offspring being male or female is proportional to the number of sperm that carry either X or Y chromosomes. And imagine that this ratio is controlled by a gene, and that initially, the gene is such that across the whole population, 17 sperm carry an X chromosome for each that carries a Y chromosome. In this population, any male who has a mutation in this gene resulting in them producing a closer-to-equal number of X and Y sperm will have a reproductive fitness advantage, because they will have more male children amidst a majority-female population. Those mutations will therefore spread until the advantage disappears.
In order for 17-to-1 female:male ratio to be stable, you'd basically need to have a period of thousands of years in which, for whatever reason, 16/17ths of women do not reproduce. That's the exact opposite of the condition described in this article.