Could feminism prolong average human life expectancy?

Here's an interesting argument I came across in my reading about evolutionary theory. It might be usable as a powerful new argument in favour of the social changes engendered by the rise of feminism since the 1970s.

So, I'm sure you all know this already, but since feminism began to really gather steam in the 1970s, the average age for men and women to get married and have children has been steadily climbing. I don't have the exact figures, but it's rather significant. People think that's significant because the chances of genetic deformity or other forms of gene-based deficiency rises precipitously as the mother AND father get older. Basically, older ova and sperm are more likely to yield offspring with gene-based adverse conditions such as down's syndrome.

But that's a good thing, actually, although on the face of it, that state of affairs sounds terrible.

Basically, the evolutionary argument is that humans have, on the genetic level, developed immunities to a vast array of illnesses and other environmental pathogens or genetic maladaptions that will lead to an early death. Natural selection ensures this, because a person who lacks the genetic defences against illness or maladaption will not live to produce offspring, and thus those genes will be removed from the gene-pool upon the person's death. What we have not developed genetic defences against, however, are those illnesses that kill us after we tend to have children. That's why hereditary illnesses like heart disease and cancer still exist: because we tend to get killed by those illnesses after we pass on the genes that do not defend against them to the next generation.

So, the argument goes, if humans were to collectively push back the age at which we produce offspring, gradually over time those individuals who do not carry genes that will promote those kinds of disease will come to dominate the gene pool, in which case humans will, on average, come to live longer, since fewer of us will be killed off earlier by things like cancer.

To bring things back to feminism, humans are, partially because of feminism, presently engaged in a process of pushing back the average age at which we produce offspring. In theory, then, this could set in motion the process of natural selection of those offspring from parents who do not carry genes for diseases like cancer.

An additional factor that we must acknowledge is the effect of eugenics. Like it or not, in the near future, doctors will be able to give expecting couples a full genetic read-out of their unborn foetus, including genetic pre-dispositions to certain diseases and/or disorders. I think it's inevitable that, given such information, a large number of couples will choose to eugenically abort pregnancies where the foetus shows such signs of genetic pre-dispositions to such maladaptions. This, too, will tend to increase the average human life expectancy.