Sylvia Ann Hewlett did, after all, have some real facts on her side: it is true that as a woman ages, her egg quality does decline and pregnancy becomes both riskier and harder to achieve. Older eggs do have a higher chance of contributing to genetic abnormalities and early miscarriages. The American Society for Reproductive Medicine reports that while a thirty year-old woman has a 1 in 385 chance of having a baby with a chromosomal abnormality, that chance has risen to 1 in 192 by the time she is 35. By the time she reaches forty, she has a one in 66 chance. It is also true that women have a harder time getting pregnant as they get older. A 2004 study published in the journal Human Reproduction, finds that 75 percent of women who start trying to conceive naturally at age thirty will succeed in a year. At age thirty-five, about 66 percent will conceive in a year, and 44 percent at age 40.
But Hewlett also missed some really important facts. Medically speaking, the dangers of a having a child after age thirty –five have become significantly reduced by developments such as non-invasive genetic screening and diagnostic pregnancy tests. And while Hewlett's statistics of the likelihood of getting pregnant at various life stages are correct, they are only statistics. In fact, every woman had her own distinct biology, and the variations between women are massive. . In her 2005 book Everything Conceivable: How Reproductive Technology is Changing Men, Women and The World, Washington Post Journalist Liza Mundy eloquently describes the reality of this blurring line: "After thirty--five, women enter a period of extreme variability. A woman may remain fertile for ten years or she may undergo a precipitous drop in her ability to conceive; her childbearing may be over. As a rough gauge, doctors assume that infertility usually sets in ten years before menopause, which begins, on average, at age fifty-one."
Hewlett left out another important point as well: an increasing amount of evidence shows that aging affects men's biological clocks as well. Today men make up more than half of the cases of infertility. Sperm does not decline in quality in such a drastic way as eggs, but scientific evidence does point to the fact that sperm does age. In a 2006 study of the Isreali military database of men, researchers studied men to determine whether there was a correlation between paternal age and the incidence of autism and related disorders. They found that children of men who became a father at 40 or older were 5.75 times as likely to have autism disorder as those whose fathers younger than 30. So it is quite likely that as the age of marriage and child bearing rises both for men and women across America, poor sperm quality rather than poor egg quality will often be the culprit causing problems for many couples. But where are all the cover stories on that?