Ah yes, because today's demographies without easy access to birth control are rocketing past us in fitness.
Increased female reproductive choice (of whether and with whom to mate) yields an upward trend in fitness because it results in fewer, better cared for offspring.
> Ah yes, because today's demographies without easy access to birth control are rocketing past us in fitness.
It takes a lot longer than that, and it would be impossible to measure due to birth control being correlated with medical care.
> ...yields an upward trend in fitness because it results in fewer, better cared for offspring.
The level of care to an offspring has no effect on its genes, and if anything can mask genetic weakness by substituting extra care. So it does not cause an upward trend for the children of the offspring.
Interestingly one trait that is being selected for is female non-sensitivity to hormone contraceptives. Now that would be interesting to measure.
Another trait that is theoretically being selected for is behaviors that would discourage contraceptive use (physical or hormone based), but I doubt that that would be measurable - at least not for many more generations.
It's an interesting world we've made for ourself, I would love to see demographics for 250 years from now.
Increased female reproductive choice (of whether and with whom to mate) yields an upward trend in fitness because it results in fewer, better cared for offspring.