Yes, the "freezing before chemo" scenario was one that occurred to me as well. Men who are going to undergo chemo and subsequently be rendered sterile often freeze sperm. I'm not saying it's right but the prospect of permanent infertility is a terrifying one.

Tim J., actually, for what it is worth, a woman's fertility already begins to decline in her late 20s.
Also, regarding the frozen eggs, my father is actually is a leader in this field. To date, he (as an infertility physician) has had the most babies born using frozen eggs (not the most pregnancies, an "honor" which goes to an Italian physician). As an orthodox Catholic, I do not condone infertility procedures wherein fertilization occurs outside the body. I feel compelled, however, to prevent an overgeneralization of the motives of many of those involved. As a devout Evangelical Protestant OB/GYN and infertility specialist, my father wanted to provide women an alternative to freezing embryos, wherein a human being is frequently killed. In addition, many of his patients freeze eggs prior to radiation or chemotherapy treatments for cancer that will, as a side effect, destroy their ovaries. Again, I am morally opposed to fertilization outside the body. I also recognize that some doctors and patients will use this medical technology in very selfish ways (as Michelle correctly highlighted). I thought it is worth noting, however, than there are other motivations that are far more noble, even if still outside the bounds of Catholic sexual/reproductive morality.

I'd just add one more disclaimer - the exceptional cases where a wife is less suitable for the childcaring role than her husband, for whatever reason, addressed by point #11 here. Not to make it seem more widespread than it is, but it does happen.
I can't help but also think a lot of women work in their earlier years out of necessity, for building their future nests. Isn't it true that while the cost of living has gone up, wages per person decreased?
Someone in a forum once pointed out how their barber father made very little money and only had business 50% of the day, yet still managed to buy a house and support a decent-sized family. Today they would need all sorts of aid--and fewer children--to be able to just scrape by. These women would have to seriously consider delaying marriage and thus children, not that this legitimizes the freezing of their eggs.

I believe one of the reasons that fertility declines after thirty-five or so, is that after that we are just too TIRED to raise children.
It's exhausting work, with little sleep, and people in their twenties and early thirties are much better equipped for that kind of schedule.