Pregnancy tips What is society's problem with older moms?

It seems like there's never a shortage of articles about "how old is too old to have a baby"...here is an article that discusses that question:

news.bbc.co.uk

From the article:

Imagine walking past a poster on the street. It shows a mother and baby. The mother, however, is old enough to be the baby's grandmother. The initial reaction of many passers-by, upon being told that this grey-haired and wrinkled woman is the mother, would be one of revulsion. There is something deeply unnatural about the image.

These are the thoughts that many have had in response to the news that Susan Tollefsen, who became a mother at 57, is now considering IVF treatment again at the age of 59. But is there a rational basis for concern?