This is from the book "Genetics For A New Human Ecology".

It's sort of a discussion of de novo mutations (mostly occurring at recombination), mutations that didn't exist in the previous generation. It is about the genetic disaster from accumulated broken genes leading to a bad genetic load, because what we call human progress is the removal of natural selection. The book is about how to overcome the problem, including the problems from age.

"What makes these changes so problematic is that we have already changed some important habits. It used to be that typically humans started reproducing in their mid-teens. Now we have changed it to where it is considered ideal for a woman to start a family in her early thirties when she is more mature and better positioned in life. Unfortunately, there are a lot more copy errors created in the sex cells as we age. This is especially true for women and for a woman of age 35, it is calculated that half of her eggs will have significant genetic problems. This effects men as well, but not as much. The problem relates to reduced oxygen levels around the woman's ovaries. By age 45 it is calculated that 95% of her eggs have significant abnormalities in their genes. To reduce this problem, there is the possibility of freezing eggs when a woman is young and fewer mutations have occurred, for later use when she is ready to have a family. Perhaps a tissue sample could be saved from youth and manipulated to produce sex cells later. Unfortunately, that will not effect what happens at recombination. The basic problem will still occur and it is not the only problem or even the main part of the problem. At the same time that copy errors have been increasing, we have been greatly reducing natural selection. We call it human progress. It is impossible to completely remove natural selection, but we have greatly reduced it and in particularly important ways. Partly it is advances in medicine, including vaccines. It is also better nutrition which used to contribute to a lot of mortality in infants and children. It used to be that in many societies, children were not named until after the first year, (or as they looked at it, until after the first winter) because the infant mortality rate was so high. That does not even include the natural selection rate before birth that is from known and unknown miscarriages. In history, typically no more than 50% of children born survived to reproduce. That is a pretty high selection rate."